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Evidence evaluation report —
Cell-free DNA testing for chromosomal anomalies
DRAFT 16 May 2017
Prepared by Ampersand Health Science Writing for the
Australian Government Department of Health
2
Contents
EVIDENCE EVALUATION REPORT — CELL-FREE DNA TESTING FOR CHROMOSOMAL ANOMALIES .................. 1 PROCESS OF THE REVIEW ........................................................................................................................................ 4
Research questions .......................................................................................................................... 4 Search strategy ................................................................................................................................ 4 Exclusion criteria ............................................................................................................................... 4 Assigning level of evidence ............................................................................................................ 7 Study design definitions ................................................................................................................... 7 Selection of outcomes for GRADE analysis ................................................................................... 9
EVIDENCE TABLES .................................................................................................................................................. 10 1. Are there additional benefits and costs associated with replacing the first trimester serum and
nuchal translucency screening with non-invasive prenatal testing (cell-free DNA testing)? ......... 10 1.1 Evidence summary ...................................................................................................................................... 10
Systematic literature reviews ........................................................................................................ 10 Observational studies .................................................................................................................... 10 Implementation of cell-free DNA as a first- or second-line test ................................................ 11 Cell-free DNA testing as a replacement for combined first trimester screening .................... 11 Cell-free DNA testing as second-line testing............................................................................... 12 Impact of cell-free DNA testing on screening practices and invasive procedures ............... 12 Factors affecting women’s uptake of cell-free DNA testing .................................................... 13 Cost-effectiveness of cell-free DNA testing ................................................................................ 13 Additional information ................................................................................................................... 13 Advice to EWG ............................................................................................................................... 13
1.2 Evidence statements .................................................................................................................................. 14 1.3 Summary of findings .................................................................................................................................... 15
Cell-free DNA testing compared to cFTS for detection of fetal chromosomal anomalies ... 15 Second-line cfDNA testing compared to cFTS for detection of fetal chromosomal
anomalies ....................................................................................................................................... 16 1.4 Reported rates of detection and false positives and positive predictive values with cell-free
DNA testing .................................................................................................................................................... 17 Systematic reviews ......................................................................................................................... 17 Observational studies .................................................................................................................... 22
1.5 Cell-free DNA testing as a replacement for first trimester serum and nuchal translucency
screening ........................................................................................................................................................ 30 Systematic reviews ......................................................................................................................... 30 Prospective cohort studies ............................................................................................................ 31 Retrospective cohort studies ........................................................................................................ 32 Modelling studies ........................................................................................................................... 38
1.6 Cell-free DNA combined with cFTS......................................................................................................... 41 Prospective cohort studies ............................................................................................................ 41 Retrospective cohort studies ........................................................................................................ 43 Modelling studies ........................................................................................................................... 52
1.7 Impact of cell-free fetal DNA testing on screening practices and invasive procedures ....... 55 1.8 Factors affecting uptake of cell-free fetal DNA testing by women.............................................. 70 1.9 Cost-effectiveness of cell-free DNA testing ......................................................................................... 77
Australian studies ............................................................................................................................ 77 Overseas studies............................................................................................................................. 79
1.10 Guidelines and statements for research question 1 .......................................................................... 87 1.11 Excluded studies for research question 1.............................................................................................. 91
Background papers ....................................................................................................................... 91
3
Systematic reviews excluded due to low quality or overlap with high-quality systematic
reviews............................................................................................................................................. 98 Studies included in high-quality systematic reviews included in this review ........................... 99 Level IV studies ............................................................................................................................. 105 Other excluded studies ............................................................................................................... 106
2. Are there specific issues for Aboriginal and Torres Strait Islander women and rural and remote
populations? ......................................................................................................................................................... 116 REFERENCES ......................................................................................................................................................... 117
4
PROCESS OF THE REVIEW
Research questions
1. Are there additional benefits and costs associated with replacing the first trimester serum and nuchal
translucency screening with non-invasive prenatal testing (cell-free deoxyribonucleic acid [cfDNA]
testing)?
2. Are there specific issues for Aboriginal and Torres Strait Islander women and rural and remote
populations?
Search strategy
Databases searched:
• MEDLINE (OVID) and PSYCHINFO (OVID) = 547
• EMBASE = 1388
• COCHRANE LIBRARY = 24
• CINAHL = 133
• AUSTRALIAN INDIGENOUS HEALTHINFONET = 0
Date of searches: 10/05/2016
Dates searched: 2008 to present
Full search strategies
MEDLINE AND PSYCHINFO (OVID)
1. Exp Pregnancy/
2. Exp Prenatal Care/
3. Exp Fetus/
4. (prenatal* or pre-natal* or pre natal or antenatal* or ante-natal* or ante-natal or maternal* or
pregnan* or fetus* or foetus* or fetal* or foetal*).tw.
5. 1 or 2 or 3 or 4
6. ((noninvasive or non-invasive or non invasive) adj3 (diagnos* or test* or detect* or screen*)).tw.
7. (NIPT or NIPD).tw.
8. (cfDNA or cffDNA or ccffDNA or ffDNA or cell free DNA or free fetal DNA or free foetal DNA).tw.
9. 6 or 7 or 8
10. exp Down Syndrome/
11. exp Aneuploidy/
12. (down* adj syndrome).tw.
13. (trisomy* or aneuploid*).tw.
14. 10 or 11 or 12 or 13
15. 5 and 9 and 14
16. 2008 to current
EMBASE
1. 'pregnancy'/exp
2. 'prenatal care'/exp
3. 'fetus'/exp
4. prenatal*:ab,ti OR 'pre natal*':ab,ti OR 'pre-natal*' OR antenatal*:ab,ti OR 'ante natal*':ab,ti
OR 'ante-natal*' OR maternal*:ab,ti OR pregnan*:ab,ti OR fetus*:ab,ti OR foetus*:ab,ti
OR fetal*:ab,ti OR foetal*:ab,ti
5. Or 1-4
6. ((noninvasive OR 'non-invasive' OR 'non invasive') AND
(diagnos* OR test* OR detect* OR screen*)):ab,ti
7. nipt:ab,ti OR nipd:ab,ti
8. cfdna:ab,ti OR cffdna:ab,ti OR ccffdna:ab,ti OR ffdna:ab,ti OR 'cell free dna':ab,ti OR 'free
fetal dna':ab,ti OR 'free foetal dna':ab,ti
9. Or 6-8
10. 'down syndrome'/exp
11. 'trisomy'/exp
12. 'aneuploidy'/exp
13. trisom*:ab,ti OR aneuploid*:ab,ti
14. (down* NEXT/1 syndrome):ab,ti
15. Or 10-14
16. 5 AND 9 AND 15
17. 2008 to current
5
COCHRANE LIBRARY
1. MeSH descriptor: [Pregnancy] explode all trees
2. MeSH descriptor: [Prenatal Care] explode all trees
3. MeSH descriptor: [Fetus] explode all trees
4. (prenatal* or 'pre natal*' or pre-natal* or antenatal* or 'ante natal*’or ante-
natal* or maternal* or pregnan* or fetus* or foetus* or fetal* or foetal*):ti,ab,kw
5. 1 or #2 or #3 or #4
6. ((noninvasive or 'non-invasive' or 'non invasive') and
(diagnos* OR test* OR detect* OR screen*)):ti,ab,kw
7. (nipt or nipd):ti.ab,kw
8. (cfdna or cffdna or ccffdna or ffdna 'cell free dna' or 'free fetal dna'or 'free foetal
dna'):ti,ab,kw
9. #6 or #7 or #8
10. MeSH descriptor: [Down Syndrome] explode all trees
11. MeSH descriptor: [Aneuploidy] explode all trees
12. (trisom* or aneuploid*):ti,ab,kw
13. (down* next/1 syndrome):ti,ab,kw
14. #10 or #11 or #12 or #13
15. #5 and #9 and #14
16. 2008 to current
CINAHL
1. (MH “Pregnancy+”)
2. (MH “Prenatal Care+”)
3. (MD “Fetus+”)
4. (prenatal* or 'pre natal*' or pre-natal* or antenatal* or 'ante natal*’or ante-
natal* or maternal* or pregnan* or fetus* or foetus* or fetal* or foetal*)
5. S1 OR S2 OR S3 OR S4
6. ((noninvasive or 'non-invasive' or 'non invasive') and
(diagnos* OR test* OR detect* OR screen*))
7. (nipt or nipd)
8. (cfdna or cffdna or ccffdna or ffdna 'cell free dna' or 'free fetal dna'or 'free foetal dna')
9. S6 OR S7 OR S8
10. (MH “Down Syndrome+”)
11. (MH “Aneuploidy+”)
12. (trisom* or aneuploid*)
13. (down* N1 syndrome)
14. S10 OR S11 OR S12 OR S13
15. S5 AND S9 AND S14
16. 2008 to current
AUSTRALIAN INDIGENOUS HEALTHINFONET
Title: Non invasive prenatal testing
Title: NIPT
2008 to current
6
Prisma flow diagram
Exclusion criteria
Full texts of studies were reviewed. Studies were excluded for the following reasons:
• background information
• systematic review of low quality or overlapping with high-quality systematic review
• already included in high quality systematic reviews
• level IV evidence
• does not answer research question
• not in English
• does not meet criteria for grading (eg no outcomes reported, reporting too limited to establish risk
of bias)
• narrative review or opinion paper (editorial, letter, comment)
• potential conflict of interest (industry study).
The remaining 59 studies were analysed in the review.
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Assigning level of evidence
Levels of evidence were assigned using the NHMRC levels (screening intervention as cfDNA testing is
considered a screening rather than a diagnostic test) and the definitions given below. No evidence
was identified for research question 2.
Designations of levels of evidence according to type of research question
Level Screening intervention
I A systematic review of level II studies
II A randomised controlled trial
III-1 Pseudo-randomised controlled trial
(ie alternate allocation or some other method)
III-2 A comparative study with concurrent controls:
▪ Non-randomised, experimental trial
▪ Cohort study
▪ Case-control study
III-3 A comparative study without concurrent controls:
Historical control study
Two or more single arm study
IV Case series
Source: NHMRC (2009) NHMRC levels of evidence and grades of recommendations for developers of guidelines.
Study design definitions
• A study of test accuracy with: an independent, blinded comparison with a valid reference standard,
among consecutive patients with a defined clinical presentation — a cross-sectional study where a
consecutive group of people from an appropriate (relevant) population receive the test under
study (index test) and the reference standard test. The index test result is not incorporated in (is
independent of) the reference test result/final diagnosis. The assessor determining the results of the
index test is blinded to the results of the reference standard test and vice versa.
• A study of test accuracy with: an independent, blinded comparison with a valid reference standard,
among non-consecutive patients with a defined clinical presentation — a cross-sectional study
where a non-consecutive group of people from an appropriate (relevant) population receive the
test under study (index test) and the reference standard test. The index test result is not
incorporated in (is independent of) the reference test result/final diagnosis. The assessor
determining the results of the index test is blinded to the results of the reference standard test and
vice versa.
• Case series — a single group of people exposed to the intervention (factor under study). Post-test –
only outcomes after the intervention (factor under study) are recorded in the series of people, so no
comparisons can be made. Pre-test/post-test – measures on an outcome are taken before and
after the intervention is introduced to a series of people and are then compared (also known as a
‘before- and-after study’).
• Case-control study — people with the outcome or disease (cases) and an appropriate group of
controls without the outcome or disease (controls) are selected and information obtained about
their previous exposure/non-exposure to the intervention or factor under study.
• Diagnostic (test) accuracy – in diagnostic accuracy studies, the outcomes from one or more
diagnostic tests under evaluation (the index test/s) are compared with outcomes from a reference
standard test. These outcomes are measured in individuals who are suspected of having the
condition of interest. The term accuracy refers to the amount of agreement between the index test
and the reference standard test in terms of outcome measurement. Diagnostic accuracy can be
expressed in many ways, including sensitivity and specificity, likelihood ratios, diagnostic odds ratio,
and the area under a receiver operator characteristic (ROC) curve.
8
• Diagnostic case-control study – the index test results for a group of patients already known to have
the disease (through the reference standard) are compared to the index test results with a
separate group of normal/healthy people known to be free of the disease (through the use of the
reference standard). In this situation patients with borderline or mild expressions of the disease, and
conditions mimicking the disease are excluded, which can lead to exaggeration of both sensitivity
and specificity. This is called spectrum bias because the spectrum of study participants will not be
representative of patients seen in practice. Note: this does not apply to well-designed population
based case-control studies.
• Historical control study – outcomes for a prospectively collected group of people exposed to the
intervention (factor under study) are compared with either (1) the outcomes of people treated at
the same institution prior to the introduction of the intervention (ie. control group/usual care), or (2)
the outcomes of a previously published series of people undergoing the alternate or control
intervention.
• Non-randomised, experimental trial - the unit of experimentation (eg. people, a cluster of people) is
allocated to either an intervention group or a control group, using a non-random method (such as
patient or clinician preference/availability) and the outcomes from each group are compared. This
can include:
— a controlled before-and-after study, where outcome measurements are taken before and after
the intervention is introduced, and compared at the same time point to outcome measures in
the (control) group.
— an adjusted indirect comparison, where two randomised controlled trials compare different
interventions to the same comparator ie. the placebo or control condition. The outcomes from
the two interventions are then compared indirectly.
• Prospective cohort study — where groups of people (cohorts) are observed at a point in time to be
exposed or not exposed to an intervention (or the factor under study) and then are followed
prospectively with further outcomes recorded as they happen.
• Pseudo-randomised controlled trial - the unit of experimentation (eg. people, a cluster of people) is
allocated to either an intervention (the factor under study) group or a control group, using a
pseudo-random method (such as alternate allocation, allocation by days of the week or odd-even
study numbers) and the outcomes from each group are compared.
• Randomised controlled trial — the unit of experimentation (eg. people, or a cluster of people4) is
allocated to either an intervention (the factor under study) group or a control group, using a
random mechanism (such as a coin toss, random number table, computer-generated random
numbers) and the outcomes from each group are compared.
• Retrospective cohort study — where the cohorts (groups of people exposed and not exposed) are
defined at a point of time in the past and information collected on subsequent outcomes, eg. the
use of medical records to identify a group of women using oral contraceptives five years ago, and
a group of women not using oral contraceptives, and then contacting these women or identifying
in subsequent medical records the development of deep vein thrombosis.
• Study of diagnostic yield — these studies provide the yield of diagnosed patients, as determined by
the index test, without confirmation of the accuracy of the diagnosis (ie. whether the patient is
actually diseased) by a reference standard test.
• Systematic literature review — systematic location, appraisal and synthesis of evidence from
scientific studies.
• Two or more single arm study – the outcomes of a single series of people receiving an intervention
(case series) from two or more studies are compared.
Source: NHMRC (2009) NHMRC levels of evidence and grades of recommendations for developers of guidelines.
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Selection of outcomes for GRADE analysis
Seven outcomes were selected on the basis of clinical impact and acceptability.
Outcome Importance Inclusion
Detection of trisomy 21 (Down syndrome) 9
Detection of trisomy 18 (Edwards syndrome) 9
Detection of trisomy 13 (Patau syndrome) 9
Detection of sex chromosome anomalies 9
Detection of atypical aneuploidies 9
Rates of invasive procedures 9
Rates of test failure 7
Costs to the health system 6
Procedure-related miscarriage 9
Key: 1 – 3 less important; 4 – 6 important but not critical for making a decision; 7 – 9 critical for making a decision
10
EVIDENCE TABLES
1. Are there additional benefits and costs associated with replacing the first trimester serum
and nuchal translucency screening with non-invasive prenatal testing (cell-free DNA
testing)?
1.1 Evidence summary
Reported rates of detection and false positives and positive predictive values with cell-free DNA testing
The review identified three systematic literature reviews (SLRs) in which cell-free DNA (cfDNA) testing was
validated against the results of invasive tests (amniocentesis or chorionic villus sampling [CVS]). There was
considerable overlap in included studies between SLRs and all were based on observational evidence. The
earliest SLR (Gil et al 2015b) did not include the two largest studies. The majority of studies included in the
systematic reviews used samples from women with a high risk of fetal aneuploidy.
In addition, observational studies from Australia (McLennan et al 2016), China (Shi et al 2015), France (Benachi et al
2015), Thailand (Manotaya et al 2016), the United States (Meck et al 2015; Neufeld-Kaiser et al 2015) and the United
Kingdom (Gil et al 2013; Nicolaides et al 2014) were identified. The study population comprised women at high risk
of fetal aneuploidy in all but three of the studies (Gil et al 2015b; Manotaya et al 2016; McLennan et al 2016).
Systematic literature reviews
SLRs reported pooled detection and false positive rates (FPRs) in the ranges given below (Gil et al 2015b; Mackie
et al 2016; Taylor-Phillips et al 2016).
Chromosomal anomaly Pooled detection rate (95%CI) Pooled false positive rate (95%CI)
Trisomy 21 99.2% (98.5 to 99.6%) to 99.4% (98.3 to 99.8%) 0.09% (0.05 to 0.14%) to 0.1% (0.0 to 0.1%)
Trisomy 18 96.3% (94.3 to 97.9%) to 97.7% (95.2 to 98.9) 0.01% (0.0 to 0.1%) to 0.13% (0.07 to 0.20%)
Trisomy 13 90.6% (82.3 to 95.8%) to 97.4% (86.1 to 99.6%) 0.0% (0.0 to 0.1%) to 0.13% (0.05 to 0.26%).
Monsomy X 90.3% (85.7 to 94.2%) to 92.9% (99.5 to 99.9%) 0.1% (0.1 to 0.5%) to 0.23% (0.14–0.34%)
Other sex chromosome
anomalies
93.0% (85.8–97.8%) 0.14% (0.06–0.24%)
Inclusion of test failures in an intention-to-screen analysis in the meta-analysis decreased detection rates by
1.7% for trisomy 21, 1.6% for trisomy 18 and 7.1% for trisomy 13 (Taylor-Phillips et al 2016).
Observational studies
In observational studies that reported detection and FPRs, these were as given below.
Chromosomal anomaly High-risk population
(Benachi et al 2015)
Mixed-risk population
(Manotaya et al 2016)
Detection* FPR* Detection (95%CI) FPR*
Trisomy 21 100% 0.1% 100% (89.72 to 100.0%) 0.02%
Trisomy 18 88% 0.1% 100% (78.2 to 100.0%) 0.08%
Trisomy 13 100% 0.1% 100% (59.04 to 100.0%) 0.02%
* 95% confidence intervals not reported.
One study reported that cfDNA testing detected all cases of triploidy (n=4) in cases where the extra haploid
set was of paternal origin (Nicolaides et al 2014).
In studies where positive predictive value1 (PPV) was reported, for trisomies 21, 18, 13 and sex chromosome
aneuploidies taken together, this was 77.4 % (n=55; 95%CI, 63.4 - 87.3) (Neufeld-Kaiser et al 2015). For individual
chromosomal aneuploidies, PPV was as given below.
1 The probability that subjects with a positive result are true positives, calculated as true positives divided by total positives.
Higher prevalence of the condition being screened increases the PPV.
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Chromosomal
anomaly
High-risk population Mixed-risk population
(Meck et al 2015) (Manotaya et al 2016) (McLennan et al 2016)
n PPV (95%CI) n PPV (95%CI) n PPV*
Trisomy 21 99 93% (86.0 to 97.1) 31 94.4% (81.34 to 99.32%) 44 91.4%
Trisomy 18 24 58% (36.6 to 77.9%) 16 79.0% (54.43 to 93.95%) 11 58.3%
Trisomy 13 11 45% (16.7 to 76.6%) 5 87.5% (47.35 to 99.68%) 2 50.0%
Monsomy X 26 23% (9 to 43.6%) — 24 25.0%
XXY 6 67% (22.3 to 95.7%) — 11 54.5%
* 95% confidence intervals not reported.
One study (Benachi et al 2015) found that rates of additional aneuploidies (sex chromosome anomalies and
triploidy) not identified by cfDNA were significantly higher among women with fetal anomalies on ultrasound
(structural or ‘soft’ markers) than among those without (7.9 vs 0.4%; p<0.01). Another noted that ultrasound
detection of fetal structural anomalies resulted in detection of additional chromosomal anomalies not
identified by cfDNA testing (McLennan et al 2016).
Rates of inconclusive primary test results (eg due to assay failure or low fetal fraction) were reported as 0.6%
(Neufeld-Kaiser et al 2015), 0.7% (Benachi et al 2015), 2.4% (McLennan et al 2016) and 4.8% (Gil et al 2015b). Repeated
test failure was reported to be associated with body mass index greater than 30 kg/m2 (fetal fraction is lower
due to increased maternal circulatory volume) (Benachi et al 2015; McLennan et al 2016). One study (Shi et al 2015)
noted that median fetal fraction was lower in the first trimester than in the second but that an increase was
only observed in 59% of pregnancies.
Studies noted that, given that both false negative and false positive results occur, cfDNA is an advanced
screening test rather than a diagnostic test and that this is an important aspect of pretest counselling (Gil et al
2015b; Meck et al 2015; Neufeld-Kaiser et al 2015; McLennan et al 2016).
Implementation of cell-free DNA as a first- or second-line test
Studies identified considered a range of models for antenatal testing for chromosomal anomalies. This review
focuses on those that considered cfDNA testing as a first-line test (ie as a replacement for combined first
trimester screening [cFTS], which involves maternal serum and nuchal translucency screening) and as a
second-line screen (ie offered to women identified as at high-risk by cFTS).
One SLR was identified that aimed to derive pooled detection and false positive rates for aneuploidies other
than trisomy 21 with different antenatal screening approaches (Metcalfe et al 2014).
Additional observational studies identified comprised:
• prospective cohort studies from Australia (McLennan et al 2016) and the United Kingdom (Gil et al 2013)
• studies that reviewed retrospective data from cohorts in Australia (Susman et al 2010; O'Leary et al 2013;
Maxwell et al 2015), Belgium (Gyselaers et al 2015), Denmark (Petersen et al 2014), Germany (Kagan et al 2015a;
Kagan et al 2015b), the Netherlands (Lichtenbelt et al 2015), Sweden (Conner et al 2015), the United Kingdom
(Syngelaki et al 2014; Khalil et al 2015) and the United States (Kaimal et al 2015) and estimated the detection of
chromosomal anomalies had cfDNA testing been used as first- or second-line testing
• studies that investigated outcomes from different models of cfDNA testing in a hypothetical cohort of
women (Morris et al 2014; Kaimal et al 2015; Mersy et al 2015)
• an Australian study that investigated risk thresholds for eligibility for cfDNA as second-line testing (Maxwell et
al 2016).
There was some inconsistency in the evidence, largely due to assumptions underlying modelling (ie the
chromosomal anomalies included in the cfDNA test panel, sensitivity and specificity ascribed to cfDNA testing,
inclusion of cfDNA test failures in calculations and risk thresholds used for invasive testing).
Cell-free DNA testing as a replacement for combined first trimester screening
Prospective cohort and retrospective cohort and modelling studies were consistent in finding higher detection
rates for trisomy 21 with cfDNA testing than with cFTS (Susman et al 2010; Morris et al 2014; Syngelaki et al 2014;
Gyselaers et al 2015; Kagan et al 2015a; Kagan et al 2015b; Mersy et al 2015; McLennan et al 2016), lower numbers of
12
invasive procedures (Susman et al 2010; Syngelaki et al 2014; Kagan et al 2015a) and procedure-related miscarriages
(Morris et al 2014; Gyselaers et al 2015; Mersy et al 2015).
A systematic review (Metcalfe et al 2014) found that, compared to cFTS, cfDNA testing had higher detection
rates and lower FPRs for trisomy 13 (90.3 vs 83.1%; FPR 0.2 vs 4.4%), trisomy 18 (98.1% vs 91.9%; FPR 0.2 vs 3.5%)
and 45X (92.2 vs 70.1%; FPR 0.1 vs 5.4%). Most estimates on cfDNA testing came from high-risk samples.
In a prospective cohort study, detection of trisomy 18 was higher with cfDNA testing than with cFTS (McLennan
et al 2016). In retrospective cohort studies, rates of detection of trisomies 18 and 13 with cfDNA testing were
estimated to be higher (Petersen et al 2014; Syngelaki et al 2014), similar (Kagan et al 2015a) or lower (Susman et al
2010). Detection of sex chromosome aneuploidies was estimated to be higher (Kagan et al 2015a) or lower
(Susman et al 2010; Syngelaki et al 2014) and atypical aneuploidies were not detected (Petersen et al 2014; Kagan et
al 2015a). One study found that nuchal translucency measurement (in addition to cfDNA testing) would identify
an additional 0.01% of chromosomal anomalies (Lichtenbelt et al 2015). One modelling study suggested that
cfDNA would be optimal for women aged 40 years and older (Kaimal et al 2015).
Rates of primary test failure were estimated to be in the range of 1.7–2.4% (Gil et al 2013; Syngelaki et al 2014).
Studies noted the importance of counselling women about the ability of the test to identify chromosomal
anomalies other than trisomy 21 (Susman et al 2010; Metcalfe et al 2014).
Cell-free DNA testing as second-line testing
There was some inconsistency in findings on detection of trisomy 21 with second-line cfDNA testing compared
to cFTS alone — some studies estimated that rates of detection would be increased (Syngelaki et al 2014; Conner
et al 2015; Kagan et al 2015a; Kagan et al 2015b; McLennan et al 2016), while others estimated that rates of detection
would be similar (O'Leary et al 2013; Morris et al 2014; Gyselaers et al 2015; Mersy et al 2015).
Rates of detection with second-line cfDNA testing were estimated to be higher than with cFTS alone for trisomy
18 (Syngelaki et al 2014; Kagan et al 2015a; McLennan et al 2016), higher (Syngelaki et al 2014) or similar (Kagan et al
2015a) for trisomy 13, higher for sex chromosome aneuploidies (Syngelaki et al 2014; Kagan et al 2015a), and lower
for triploidy (Syngelaki et al 2014) and atypical aneuploidies (Syngelaki et al 2014; Kagan et al 2015a).
One study, in which women were screened by cfDNA at 10 weeks and the combined test at 12 weeks, found
that while detection was similar between the two approaches, false positives were higher for cFTS alone (3.4 vs
0.1%) (Gil et al 2013).
Studies estimated that numbers of invasive diagnostic procedures (O'Leary et al 2013; Syngelaki et al 2014; Kagan et
al 2015a; Kaimal et al 2015; Mersy et al 2015) and procedure-related miscarriage would be lower (Gyselaers et al
2015; Khalil et al 2015) with second-line cfDNA testing than with cFTS alone.
Relevant considerations in implementing second-line testing were maternal age (Kaimal et al 2015; Maxwell et al
2016), risk threshold (Maxwell et al 2016) and the need for clear indicators for invasive testing over cfDNA testing
to optimise detection of rare pathogenic anomalies (Maxwell et al 2015).
Impact of cell-free DNA testing on screening practices and invasive procedures
Studies have described changes in practice following the introduction of cell-free DNA testing in Australia
(Robson & Hui 2015), China (Li et al 2016), Hong Kong (Chan et al 2015; Poon et al 2015), Japan (Hasegawa et al 2015),
Switzerland (Manegold-Brauer et al 2014; Manegold-Brauer et al 2015) and the United States (Chetty et al 2013; Friel et
al 2014; Larion et al 2014b; Larion et al 2014a; Pettit et al 2014; Platt et al 2014; Shah et al 2014; Larion et al 2015; Palomaki et
al 2015; Tiller et al 2015; Williams et al 2015).
The Australian study (Robson & Hui 2015) found that, in the 2 years following introduction of cell-free DNA testing,
the number of amniocenteses fell by 51% and that of chorionic villus sampling (CVS) procedures by 37%. The
study noted that this has implications for training in and maintenance of skills for these procedures.
Studies in the United States found that introduction of cell-free DNA testing reduced rates of first trimester
combined screening (Larion et al 2014b; Larion et al 2014a; Larion et al 2015), although one found only a minor
impact on serum testing rates (Palomaki et al 2015) and another that first trimester screening was only reduced
among high-risk women (Larion et al 2015). One found a considerable decrease in invasive testing (Tiller et al
2015).
Other overseas studies were largely consistent in finding a decrease in invasive testing (Larion et al 2014b; Larion
et al 2014a; Manegold-Brauer et al 2014; Pettit et al 2014; Platt et al 2014; Shah et al 2014; Chan et al 2015; Hasegawa et al
13
2015; Poon et al 2015; Williams et al 2015), although one found no difference (Manegold-Brauer et al 2015) and one
found a decrease occurred among women referred between 14 and 22 weeks and not among those referred
at <14 weeks (Friel et al 2014). A Chinese study found that invasive testing had not decreased following
introduction of cell-free DNA testing (Li et al 2016).
Factors affecting women’s uptake of cell-free DNA testing
Factors identified as affecting uptake of cell-free DNA testing included increasing risk of trisomies (Vahanian et
al 2014; Gil et al 2015a; Maiz et al 2016), increasing maternal age (Gil et al 2015a; Maiz et al 2016), nulliparity (Chan et
al 2015; Gil et al 2015a; Poon et al 2015; Maiz et al 2016) and being screened in the first rather than the second
trimester (Chetty et al 2013; Poon et al 2015). Financial issues may also affect decision-making (Vahanian et al 2014;
Han et al 2015; Poon et al 2015). None of these studies were conducted in Australia.
Cost-effectiveness of cell-free DNA testing
Two studies evaluated the cost-effectiveness of incorporating cfDNA testing for trisomy 21 into Australian
practice:
• in comparing universal cfDNA testing with current practice (combined FTS with women with a probability
of 1:300 counselled for invasive diagnostic testing), an incremental analysis (Ayres et al 2014) estimated
increased detection (an additional 123 in a theoretical population of 300,000 women) and lower rates of
procedure-related miscarriage (90 fewer) at an incremental cost of $1,094,608 per case (assuming a cost
of $575 for cfDNA testing)
• in comparing second-line cfDNA testing with current practice, one study found that the number of
procedure-related miscarriages was decreased by 51% and the cost per trisomy 21 case confirmed
increased by 9.7% (assuming 100% uptake of the screening strategy) (O'Leary et al 2013) while the other
found 0.6% reduction in detection and a 3.4–4.1% decrease in costs (Ayres et al 2014)
• the most cost-effective strategy was cfDNA for women aged >40 years, costing an incremental $81,199
per additional trisomy 21 case detected and avoiding 95 procedure-related miscarriages (Ayres et al 2014).
No Australian studies investigated the costs associated with cfDNA testing for other chromosomal anomalies.
Overseas cost-effective studies were largely consistent in finding that second-line cfDNA testing was more
cost-effective when compared with universal cfDNA testing:
• among studies conducted in the United States, one found that universal cfDNA testing would reduce
health care costs if it can be provided for $744 or less (Benn et al 2015), three found that second-line cfDNA
testing was more cost-efficient than universal cfDNA testing (Cuckle et al 2013; Evans et al 2015; Walker et al
2015) and two (with potential conflict of interest) that cfDNA testing was more cost-efficient than cFTS
(Fairbrother et al 2016; Garfield & Armstrong 2016)
• a Canadian study (Okun et al 2014) found that second-line models of cfDNA testing can improve overall
screening performance with modest increase in costs and a decrease in cost per trisomy 21 case
detected prenatally
• a Belgian study (Neyt et al 2014) found that introduction of second-line cfDNA testing (but not first-line
testing at the current price) results in cost savings
• a study in the Netherlands (Beulen et al 2014) estimated a cost increase of 21% with cfDNA implemented as
a second-line test and of 157% when implemented as a primary test compared to cFTS.
Additional information
The Medicare Benefits Schedule does not include cfDNA testing.
Sonic Genetics (for example) provides the test for $450, with repeat testing performed for no additional
charge and costs refunded if the test is unable to provide an assessment for trisomies 21, 18 and 13.
Advice to EWG
While cfDNA testing has a higher detection rate for the more common trisomies compared with combined first
trimester screening, and fewer invasive procedures are required, invasive diagnostic testing is still required for
women who test positive and costs are higher. As well, cfDNA testing does not detect less common
chromosomal anomalies that may currently be identified through ultrasound assessment (Low quality
evidence, see Summary of Findings table).
14
As cfDNA testing is already available in Australia (although not currently covered by Medicare or private
health insurance), it is important that health professionals counsel women about the chromosomal anomalies
that may (or may not) be identified by the test.
Note that while this document refers to ‘risk’ of fetal chromosomal anomaly, consistent with the literature, the
review of the guideline chapter will ensure that neutral language is used (ie ‘probability’ used rather than
‘risk’).
1.2 Evidence statements
Cell-free DNA testing compared to cFTS for detection of fetal chromosomal anomalies
• Cell-free DNA testing has a higher detection rate for the more common trisomies (trisomies 21, 18 and 13),
lower detection rates for sex chromosome and atypical aneuploidies and a lower risk of invasive
procedures compared with combined first trimester screening (low quality evidence).
Second-line cfDNA testing compared to cFTS for detection of fetal chromosomal anomalies
• Second-line cfDNA testing has a higher detection rate for the more common trisomies (trisomies 21, 18 and
13), lower detection rates for atypical aneuploidies, lower risk of invasive procedures compared with
combined first trimester screening and the difference in detection of sex chromosome aneuploidies did
not reach significance (low quality evidence).
No new recommendations were developed.
15
1.3 Summary of findings
Cell-free DNA testing compared to cFTS for detection of fetal chromosomal anomalies
Patient or population: high-risk and mixed-risk populations
Setting: Australia, Belgium, Denmark, Germany, United Kingdom
Intervention: cfDNA testing
Comparison: combined first trimester screening (maternal serum and nuchal translucency)
Outcomes Anticipated absolute effects* (95% CI) Relative effect (95% CI)
№ of participants (studies)
Quality of the evidence (GRADE)
Studies
Detection with combined FTS*
Detection with cfDNA testing#
Trisomy 21
891 per 1,000
1,000 per 1,000 (963 to 1,000)
RR 1.13 (1.08 to 1.18)
3,766 (6 observational studies)
⨁⨁◯◯
LOW 1
(Petersen et al 2014;
Syngelaki et al 2014;
Gyselaers et al 2015; Kagan
et al 2015a; Kagan et al
2015b; McLennan et al 2016)
Trisomies 18 and 13 807 per 1,000
985 per 1,000 (953 to 1,000)
RR 1.22 (1.18 to 1.26)
891 (4 observational studies)
⨁⨁◯◯
LOW 1
(Petersen et al 2014;
Syngelaki et al 2014; Kagan
et al 2015a; McLennan et al
2016)
Sex chromosome aneuploidies
655 per 1,000
153 per 1,000 (106 to 219)
RR 0.23 (0.16 to 0.33)
203 (3 observational studies)
⨁⨁◯◯
LOW1
(Syngelaki et al 2014; Kagan
et al 2015a; McLennan et al
2016)
Atypical aneuploidies 367 per 1,000
4 per 1,000 (0 to 15)
RR 0.01 (0.00 to 0.04)
498 (3 observational studies)
⨁⨁◯◯
LOW 1
(Petersen et al 2014;
Syngelaki et al 2014; Kagan
et al 2015a)
Outcomes Anticipated absolute effects* (95% CI) Relative effect (95% CI)
№ of participants (studies)
Quality of the evidence (GRADE)
Studies
Risk with combined FTS
Risk with cfDNA testing
Invasive
procedures 59 per 1,000 10 per 1,000
(10 to 11)
RR 0.17 (0.17 to 0.18)
179,237 (3 observational studies)
⨁⨁◯◯
LOW 1
(Susman et al 2010; Syngelaki
et al 2014; Kagan et al 2015a)
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio
GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect
* Risk thresholds for invasive procedures ranged from 1:100 to >1:300.
# Assumptions about the chromosomal anomalies that could be detected by cfDNA testing varied between studies.
1 Data from observational studies
16
Second-line cfDNA testing compared to cFTS for detection of fetal chromosomal anomalies
Patient or population: high-risk and mixed-risk populations
Setting: Australia, Belgium, Denmark, Germany, United Kingdom
Intervention: second-line cfDNA testing
Comparison: combined FTS alone
Outcomes Anticipated absolute effects* (95% CI) Relative effect (95% CI)
№ of participants (studies)
Quality of the evidence (GRADE)
Studies
Detection with cFTS*
Detection with second-line cfDNA testing#
Trisomy 21
863 per 1,000
932 per 1,000
(915 to 958)
RR 1.08 (1.06 to 1.11)
1,957 (5 observational studies)
⨁⨁◯◯
LOW 1
(Petersen et al 2014;
Syngelaki et al 2014;
Gyselaers et al 2015; Kagan
et al 2015a; McLennan et al
2016)
Trisomies 18 and 13 864 per 1,000
916 per 1,000 (890 to 950)
RR 1.06 (1.03 to 1.10)
888 (4 observational studies)
⨁⨁◯◯
LOW 1
(Petersen et al 2014;
Syngelaki et al 2014; Kagan
et al 2015a; McLennan et al
2016)
Sex chromosome aneuploidies
655 per 1,000
692 per 1,000 (605 to 791)
RR 1.04 (0.91 to 1.19)
197 (3 observational studies)
⨁⨁◯◯
LOW 1
(Syngelaki et al 2014; Kagan
et al 2015a; McLennan et al
2016)
Atypical aneuploidies 415 per 1,000
299 per 1,000 (237 to 382)
RR 0.72 (0.57 to 0.92)
236 (2 observational studies)
⨁⨁◯◯
LOW 1
(Syngelaki et al 2014; Kagan
et al 2015a)
Outcomes Anticipated absolute effects* (95% CI) Relative effect (95% CI)
№ of participants (studies)
Quality of the evidence (GRADE)
Studies
Risk with cFTS
Risk with second-line cfDNA testing
Invasive procedures 57 per 1,000
27 per 1,000 (25 to 28)
RR 0.48 (0.45 to 0.50)
68,664 (3 observational studies)
⨁⨁◯◯
LOW 1
(O'Leary et al 2013; Syngelaki
et al 2014; Kagan et al 2015a)
*The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: Confidence interval; RR: Risk ratio
GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect
* Risk thresholds for invasive procedures ranged from 1:100 to >1:300.
# Risk thresholds for invasive procedures ranged from 1:51–1:1,000 to >1:300.
1 Data from observational studies
17
1.4 Reported rates of detection and false positives and positive predictive values with cell-free DNA testing
Systematic reviews
Trisomy 21
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2015b)
SLR I 24
studies
Studies reported on the performance of
screening by cfDNA analysis for trisomy 21, in
a combined total of 1,051 trisomy-21 and
21,608 non-trisomy-21 singleton pregnancies.
Among individual studies, the detection rate
varied between 94.4% and 100% and the
false positive varied between 0% and 2.05%.
The pooled weighted detection and false
positive rates were 99.2% (95% CI, 98.5–
99.6%) and 0.09% (95% CI, 0.05–0.14%),
respectively.
(Mackie et
al 2016)
SLR I 31
studies
148,344 tests Bivariate meta-analysis produced a
summary sensitivity of 0.994 (95% CI 0.983–
0.998) and specificity of 0.999 (95% CI 0.999–
1.000), a positive likelihood ratio of 1720
(95%CI 1111–2662) and a negative likelihood
ratio of 0.006 (95%CI 0.002–0.017).
Of 14/31 studies reporting inconclusive
results, 7 documented an explanation (in
order of frequency): assay failure; confirmed
low fetal fraction; no reason given;
presumed low fetal fraction/inadequate
sequencing depth. The most common
reasons given for false results were:
confirmed low fetal fraction; confirmed
mosaicism; no reason given; test failure;
maternal copy number variant.
Risk of bias was
high in most
studies; all were
observational
18
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Taylor-
Phillips et al
2016)
SLR I 40
studies
The pooled sensitivity from bivariate
random-effects regression was 99.3% (98.9%
to 99.6%) and the pooled specificity was
99.9% (99.9% to 100%).
Including test failures in an intention to
diagnose analysis in the meta-analysis
decreased sensitivity estimates by 1.7% and
specificity estimates by nearly 2%.
Risk of bias was
high in most
studies; all were
observational
Trisomy 18
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2015b)
SLR I 21
studies
Studies reported on the performance of
screening by cfDNA analysis for trisomy 18, in
a combined total of 389 trisomy-18 and
21,306 non-trisomy-18 singleton pregnancies.
In individual studies, the detection rate
varied between 90.0% and 100% and the
false positive rate varied between 0% and
1.98%. The pooled weighted detection and
false positive rates were 96.3% (95% CI, 94.3–
97.9%) and 0.13% (95% CI, 0.07–0.20),
respectively.
SLR includes
case-control
studies (Level III-
3) and does not
include the two
largest studies.
19
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Mackie et
al 2016)
SLR I 24
studies
146,940 tests Bivariate meta-analysis produced a
summary sensitivity of 0.977 (95% CI0.952–
0.989) and specificity of 0.999 (95% CI 0.998–
1.00), a positive likelihood ratio of 1569 (95%
CI 810–3149) and negative likelihood ratio of
0.023 (95% CI 0.011–0.048).
Of 12/ 24 studies reporting inconclusive
results, seven documented an explanation
(in order of frequency): low fetal fraction;
test failure; no reason given; mosaicism. The
most common reasons given for false results
were: confirmed low fetal fraction;
confirmed mosaicism; presumed low fetal
fraction/human error; maternal CNV; no
reason given.
Neither test
technique nor
population risk
had a significant
effect.
(Taylor-
Phillips et al
2016)
SLR I 33
studies
The pooled sensitivity was 97.4% (95.8% to
98.4%) and specificity was 99.9% (99.9% to
100%).
Including test failures in an intention to
diagnose analysis in the meta-analysis
decreased sensitivity estimates by 1.6% and
specificity estimates by nearly 2%.
SLR included
case-control
studies (Level III-
3).
Trisomy 13
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2015b)
SLR I 18
studies
Studies reported on the performance of
screening by cfDNA analysis for trisomy 13, in
a combined total of 139 trisomy-13 and
18,059 non-trisomy-13 singleton pregnancies.
In individual studies, the detection rate
varied between 40.0% and 100% and the
false positive rate varied between 0% and
1.14%. The pooled weighted detection and
false positive rates were 91.0% (95% CI, 85.0–
95.6%) and 0.13% (95% CI, 0.05–0.26%),
respectively.
SLR includes
case-control
studies (Level III-
3) and does not
include the two
largest studies.
20
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Mackie et
al 2016)
SLR I 16
studies
134,691 tests There was a summary sensitivity of 0.906
(95% CI 0.823–0.958) and specificity of 1.00
(95% CI 0.999–1.00). The positive likelihood
ratio was 453 (95% CI 26–7864) and negative
likelihood ratio was 0.188 (95% CI 0.080–
0.44039), with a diagnostic odds ratio of
2788 (95%CI 285–27252).
Of 6/16 studies reporting inconclusive results,
4 documented an explanation for
inconclusive results: low fetal fraction;
different fragmentation rate; contamination;
assay failure; and human error. The only
reason given for false results was confirmed
low fetal fraction.
(Taylor-
Phillips et al
2016)
SLR I 24
studies
The pooled sensitivity was 97.4% (86.1% to
99.6%) and specificity was >99.9% (99.9% to
100%).
Including test failures in an intention to
diagnose analysis in the meta-analysis
decreased sensitivity estimates by 7.1% and
specificity estimates by nearly 2%.
SLR included
case-control
studies (Level III-
3).
Monsomy X
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2015b)
SLR I 16
studies
Studies reported on the detection of
monosomy X by cfDNA analysis, for a
combined total of 177 singleton
pregnancies with fetal monosomy X and
9,079 with no monosomy X.
In individual studies, the detection rate
varied between 66.7% and 100% and the
false positive rate varied between 0% and
0.52%. The pooled weighted detection and
false positive rates were 90.3% (95% CI, 85.7–
94.2%) and 0.23% (95% CI, 0.14–0.34%),
respectively.
SLR includes
case-control
studies (Level III-
3) and does not
include the two
largest studies.
21
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Mackie et
al 2016)
SLR I 8 studies 6,712 tests Bivariate meta-analysis produced a
summary sensitivity of 0.929 (95% CI 0.741–
0.984) and specificity of 0.999 (95% CI 0.995–
0.999), a positive likelihood ratio of 1337 (95%
CI 213–8407) and negative likelihood ratio of
0.071 (95% CI 0.017–0.292).
Of five of eight studies reporting
inconclusive result, three documented an
explanation (in order of frequency): low
fetal fraction; presumed human error; and
no reason given. The most common reasons
given for false results were: mosaicism and
no reason given.
The five studies that evaluated an
unselected obstetric population reported
inconclusive results, with rates of 0.29–5.10%,
and provided the same reasons for their
false and inconclusive results as with the
high-risk aneuploidy populations.
There was no
significant
difference with
test technique. It
was not possible
to assess the
effect of
population risk,
as there were
insufficient low-
risk studies.
Other sex chromosomal anomalies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2015b)
SLR I 12
studies
Studies reported on the performance of
screening by cfDNA analysis for sex
chromosome anomalies other than
monosomy X, in a combined total of 56
affected and 6,699 non-sex chromosome
aneuploidy singleton pregnancies.
The pooled weighted detection and false
positive rates were 93.0% (95% CI, 85.8–
97.8%) and 0.14% (95% CI, 0.06–0.24%),
respectively.
SLR includes
case-control
studies (Level III-
3) and does not
include the two
largest studies.
22
Observational studies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Benachi et
al 2015)
Cohort III-2 892 Aim: To evaluate the utility of noninvasive
prenatal testing using cell-free circulating
fetal DNA for detection of the three main
autosomal fetal trisomies in the setting of
ultrasonographically identified fetal
anomalies.
Setting: France
Population: women at risk of fetal
aneuploidy with or without ultrasonography
anomalies and who underwent invasive
procedures
Methods: Cell-free DNA analysis was
performed by massive parallel sequencing
and the results were compared with a fetal
karyotype.
Outcomes: Detection of trisomies 21, 18, 13,
sex chromosome anomalies, triploidy
Cell-free DNA identified 76/76 (100%) fetal
Down syndrome, 22/25 (88%) trisomy 18, and
12/12 (100%) trisomy 13.
In those with a normal ultrasonogram and
normal cfDNA analysis, karyotype identified
2/483 (0.4%) additional aneuploidies other
than trisomies 13, 18, and 21.
In those with an abnormal ultrasonogram
and a normal cell-free DNA analysis, there
were 23/290 (7.9%) additional pathogenic
karyotypes. These additional aneuploidies
included sex chromosome anomalies and
triploidy.
The rates of additional aneuploidies not
identifiable by standard cell-free DNA
screening in the two groups is significantly
different (P<0.01).
23
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2013)
Cohort III-2 1,005 Aim: To explore the feasibility of routine
maternal blood cell-free (cf) DNA testing in
screening for trisomies 21, 18 and 13 at
10 weeks gestation.
Setting: United Kingdom
Population: women with singleton
pregnancy and live fetus with CRL 32-45mm.
Median maternal age was 36.7 (range, 20-
49) years.
Methods: women were screened for
trisomies 21, 18 and 13 with blood taken for
maternal serum tests from cFTS and CFDNA
TESTING at 10 weeks and ultrasound
conducted at 12 weeks. Patient-specific risk
was assessed based on results of cFTS tests,
maternal age and history of trisomic
pregnancy.
Outcomes: Detection of trisomies 21, 18 and
13
In 11 cases the risk score for trisomy 21 and in
five cases that for trisomy 18 was >99%, in
one the risk for trisomy 13 was 34% and in
968 the risk for each of the three trisomies
was <0.01%.
The suspected trisomies were confirmed by
karyotyping after CVS, except in one case
of trisomy 18 in which the karyotype was
normal.
Both cfDNA and combined testing detected
all trisomies, but the estimated false-positive
rates (FPR) were 0.1% and 3.4%, respectively.
Risks for trisomies were provided for 957
(95.2%) cases and in 98.0% these were
available within 14 days from sampling.
In 48 (4.8%) cases no result was provided
due to problems with delivery to the
laboratory, low fetal fraction or assay failure.
Repeat sampling was performed in 40 cases
and a result obtained in 27 (67.5%) of these.
24
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Manotaya
et al 2016)
Cohort III-2 4,736 Aim: to report the clinical experience and
performance of massively parallel
sequencing-based cDNA as a screening
method in detecting trisomy 21, 18, and 13
in a mixed-risk population in Thailand.
Setting: Thailand
Population: high-risk pregnancies either with
advanced maternal age or positive serum
biochemical tests (n=2,840) and low-risk
pregnancies without conventional
indications (n=1,889).
Methods: In a 30-month period, 121 medical
centers in Thailand offered cfDNA as clinical
screening tests for fetal T21, T18, and T13 in
the mixed-risk population. All cfDNA-positive
cases were recommended to undergo
invasive prenatal diagnosis.
Outcomes: Detection of trisomies 21, 18 and
13
99.9% (4732/4736) of the participants with a
median maternal age of 35 years old
received reports, and 1.3% (63/4732) were
classified as test positive, including 36 T21, 19
T18, and 8 T13; 82.5% (52/63) took prenatal
diagnosis, and 11.5% (6/52) false-positive
cases were observed.
There were 31 T21, 16 T18, 5 T13, and 4669
euploid cases. We observed one FP of T21,
four FPs of T18 and one FP of T13 in our test,
giving the sensitivities of 100.00%, 100.00%,
and 100.00% and specificities of 99.98%,
99.92%, and 99.98% for detecting T21, T18,
and T13, respectively. The PPV for T21, T18,
and T13 were 96.77% (n=31; 83.3 to 99.9%),
75.00% (n=16; 47.6 to 92.7%), and 80.00%
(n=5; 28.4 to 99.5%), respectively. The overall
specificity for detecting these three
chromosomal anomalies combined was
99.87%, and the overall sensitivity and PPV
were 100.00% and 88.46%, respectively. The
incidence of T21, T18, and T13 were 0.64%,
0.25%, and 0.08%, respectively.
25
Study ref Design LoE N Aim, setting, population, methods Results Comments
(McLennan
et al 2016)
Cohort III-2 5,267 Aim: To assess the implementation of CFDNA
TESTING into clinical practice utilising both
first- and second-line screening models.
Setting: Metropolitan private practices in
Australia
Population: Singleton pregnancies in a
mixed risk population
Methods: cfDNA testing was offered as a
first-line screen, ideally followed by
combined first-trimester screening (cFTS), or
as a second-line test following cFTS,
particularly in those with a calculated risk
between 1:50 and 1:1000.
Outcomes: Detection of trisomies 21, 18 13,
sex chromosome aneuploidies and other
anomalies
cfDNA screening was performed in 5,267
women and as a first-line screening method
in 3,359 (63.8%). Detection rates were 100%
for trisomies 21 and 13 and 88% for
trisomy 18. Of cases with known karyotypes,
the positive predictive value (PPV) of the
test was highest for trisomy 21 (97.7%) and
lowest for monosomy X (25%).
Ultrasound detection of fetal structural
anomaly resulted in the detection of five
additional chromosome anomalies, two of
which had high-risk cFTS results.
For all chromosomal anomalies, cfDNA
alone detected 93.4%, cfDNA in a second-
line model detected 81.8% and cFTS alone
detected 65.9% (P < 0.005).
If women had only had cFTS, the rate of
invasive procedures would have been 5.5%
higher (p<0.0001).
Given the false-positive rate for all
aneuploidies, cfDNA is an advanced
screening test, rather than a diagnostic test.
Study
population may
not be
generalisable to
the Australian
obstetric
community as
women were
predominantly
older,
Caucasian and
from higher
socioeconomic
groups
26
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Meck et al
2015)
Cohort III-2 216 Aim: to determine the positive predictive
value (PPV) of noninvasive prenatal
screening (NIPS) for various aneuploidies
based on cases referred for follow-up
cytogenetic testing. Secondarily, to
determine the false-negative (FN) rate for
those cases with a negative NIPS result.
Setting: United States
Population: Pregnancies at high-risk of fetal
aneuploidy
Methods: We compared the cytogenetic
findings (primarily from chromosome
analysis) from 216 cases referred to our
laboratories with either a positive or
negative NIPS result, and classified NIPS
results as true positive, false positive, true
negative, or FN. Diagnostic cytogenetic
testing was performed on the following
tissue types: amniotic fluid (n = 137),
chorionic villi (n = 69), neonatal blood (n=6),
and products of conception (n = 4).
Outcomes: Detection of trisomies 21, 18, 13,
monosomy X, XXY
The PPV for cfDNA were as follows: 93% for
trisomy (T)21 (n=99; 95%CI 86-97.1%), 58% for
T18 (n=24; 95%CI 36.6-77.9%), 45% for T13
(n=11; 95% CI 16.7-76.6%), 23% for
monosomy X (n=26; 95% CI 9-43.6%), and
67% for XXY (n=6; 95% CI, 22.3-95.7%).
Of the 26 cases referred for follow-up
cytogenetics after a negative cfDNA result,
1 (4%) was false negative (T13). Two cases of
triploidy, a very serious condition but one
not claimed to be detectable by the test
providers, were among those classified as
true negatives.
T21, which has the highest prevalence of all
aneuploidies, demonstrated a high true-
positive rate, resulting in a high PPV.
However, the other aneuploidies, with their
lower prevalence, displayed relatively high
false-positive rates and, therefore, lower
PPV. Patients and physicians must fully
understand the limitations of this screening
test and the need in many cases to follow
up with appropriate diagnostic testing to
obtain an accurate diagnosis.
27
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Neufeld-
Kaiser et al
2015)
Cohort III-2 632 Aim: to present independent data on the
PPVs of cfDNA testing in actual clinical
practice.
Setting: United States
Population: Pregnancies at high risk of fetal
aneuploidy
Methods: Charts were retrospectively
reviewed for patients who had cfDNA and
were seen March 2012 to December 2013 in
a tertiary academic referral center. cfDNA
results were compared to diagnostic
genetic test results, fetal ultrasound results,
and clinical phenotype/outcomes. The PPV
was calculated using standard
epidemiological methods. Correlation
between screen results and both maternal
age at delivery and gestational age at time
of screening was assessed using Wilcoxon's
rank sum test.
Outcomes: Detection of trisomies 21, 18, 13
and sex chromosome aneuploidies
41 of 55 abnormal cfDNA results were
concordant with abnormal fetal outcomes,
12 were discordant, and 2 were
undetermined. The PPV for all conditions
included in the screen was 77.4 % (95 % CI,
63.4 - 87.3).
Of 578 patients with normal cfDNA results,
normal pregnancy outcome was confirmed
for 156 (27%) patients. This incomplete
follow-up of normal NIPS results does not
affect PPV calculations, but it did preclude
calculations of sensitivity, specificity, and
NPV.
Maternal age at delivery was significantly
lower for patients with abnormal discordant
results, compared to patients with abnormal
concordant results (P = 0.034). Gestational
age at time of screening was not associated
with concordance of screen results
(P=0.722).
The experience of using cfDNA in clinical
practice confirms that abnormal results
cannot be considered diagnostic. Pre-test
counseling should emphasize this.
Diagnostic genetic testing should always be
offered following abnormal cfDNA results.
28
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Nicolaides
et al 2014)
Case-
control
III-2 56 Aim: To investigate potential performance
of cell-free DNA (cfDNA) testing in maternal
blood in detecting fetal triploidy.
Setting: United Kingdom
Population: Pregnancies at high-risk of
trisomies 13, 18 and 21
Methods: Plasma and buffy coat samples
obtained at 11-13 weeks' gestation from
singleton pregnancies with diandric triploidy
(n=4), digynic triploidy (n=4), euploid fetuses
(n=48) were sent to Natera, Inc. for cfDNA
testing. Multiplex polymerase chain reaction
amplification of cfDNA followed by
sequencing of single nucleotide
polymorphic loci covering chromosomes 13,
18, 21, X, and Y was performed. Sequencing
data were analyzed using the NATUS
algorithm which identifies copy number for
each of the five chromosomes.
Outcomes: detection of fetal triploidy
cfDNA testing provided a result in 44 (91.7%)
of the 48 euploid cases and correctly
predicted the presence of two copies each
of chromosome 21, 18 and 13.
In diandric triploidy, cfDNA testing identified
multiple paternal haplotypes (indicating
fetal trisomy 21, trisomy 18 and trisomy 13)
suggesting the presence of either triploidy or
dizygotic twins. In digynic triploidy the fetal
fraction corrected for maternal weight and
gestational age was below the 0.5th
percentile.
cfDNA testing by targeted sequencing and
allelic ratio analysis of single nucleotide
polymorphisms covering chromosomes 21,
18, 13, X, and Y can detect diandric triploidy
and raise the suspicion of digynic triploidy.
29
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Shi et al
2015)
Cohort III-2 182 Aim: to determine the feasibility of early
gestational (51–84 days) cfDNA testing.
Setting: China
Population: High-risk pregnancies
Methods: Plasma DNA libraries were
subjected to MPS and chromosomal read
counts normalized to reference.
Chromosomal aneuploidy was determined
by z-scores (- 3. <. z<. 3, normal range). The
cff DNA fraction in 96 male pregnancies was
calculated by the relative proportion of Y
chromosomal reads.
Outcomes: Detection of trisomies 21, 18, 13
and 45X.
cfDNA results were obtained in the first (8-12.
weeks) and second (15-18. weeks) trimester
for 182 high-risk women.
cfDNA testing identified T21, T13 and 45,X in
3 pregnancies that were confirmed by
karyotyping, but missed a T15 pregnancy
that eventually miscarried. In the remaining
178 pregnancies, results for first and second
trimester cfDNA testing were normal.
The median fetal fraction in the first trimester
was 7.6. ±. 4.18% (compared with 10.47±4.7%
in the second trimester) and 15.6% of
samples were identified with a cff fraction
below 4%. Different trends of cff DNA
fraction change were observed between
the first and second trimester, with 59% of
pregnancies showing an increase, 17%
showing no change and 24% showing a
decrease.
30
1.5 Cell-free DNA testing as a replacement for first trimester serum and nuchal translucency screening
Systematic reviews
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Metcalfe
et al 2014)
SLR I 65
studies
Aim: to systematically review the literature
and use diagnostic meta-analysis to derive
pooled detection and false positive rates for
aneuploidies other than trisomy 21 with
different prenatal screening tests.
Non-invasive prenatal testing had the
highest detection (DR) and lowest false
positive (FPR) rates for trisomy 13 (DR: 90.3%;
FPR: 0.2%), trisomy 18 (DR: 98.1%; FPR: 0.2%),
and 45,X (DR: 92.2%; FPR: 0.1%); however,
most estimates came from high-risk samples.
The first trimester combined test also had
high DRs for all conditions studied (trisomy 13
DR: 83.1%; FPR: 4.4%; trisomy 18 DR: 91.9%;
FPR: 3.5%; 45,X DR: 70.1%; FPR: 5.4%).
31
Prospective cohort studies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(McLennan
et al 2016)
Cohort III-2 5,267 Aim: To assess the implementation of CFDNA
TESTING into clinical practice utilising both
first- and second-line screening models.
Setting: Metropolitan private practices in
Australia
Population: Singleton pregnancies in a
mixed risk population
Methods: cfDNA testing was offered as a
first-line screen, ideally followed by
combined first-trimester screening (cFTS), or
as a second-line test following cFTS,
particularly in those with a calculated risk
between 1:50 and 1:1000.
Outcomes: Detection of trisomies 21, 18 13,
sex chromosome aneuploidies and other
anomalies
cfDNA screening was performed in 5,267
women and as a first-line screening method
in 3,359 (63.8%). Detection rates were 100%
for trisomies 21 and 13 and 88% for
trisomy 18. Of cases with known karyotypes,
the positive predictive value (PPV) of the
test was highest for trisomy 21 (97.7%) and
lowest for monosomy X (25%).
Ultrasound detection of fetal structural
anomaly resulted in the detection of five
additional chromosome anomalies, two of
which had high-risk cFTS results.
For all chromosomal anomalies, cfDNA
alone detected 93.4%, cfDNA in a second-
line model detected 81.8% and cFTS alone
detected 65.9% (P < 0.005).
If women had only had cFTS, the rate of
invasive procedures would have been 5.5%
higher (p<0.0001).
Given the false-positive rate for all
aneuploidies, cfDNA is an advanced
screening test, rather than a diagnostic test.
Study
population may
not be
generalisable to
the Australian
obstetric
community as
women were
predominantly
older,
Caucasian and
from higher
socioeconomic
groups
32
Retrospective cohort studies
Trisomy 21 only
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gyselaers
et al 2015)
Cohort
study
III-2 99,619 Aim: To evaluate costs and benefits of
different scenarios for cfDNA screening.
Setting: Belgium
Population: Pregnancies screened by
combined first trimester screening (78.5%) or
second trimester screening (21.5%) in 2011
Methods: Data from the Belgian National
Institute for Health and Disability Insurance
and the Study Centre for Perinatal
Epidemiology were used in modeled
calculations of medical and economic
impact of cfDNA after prior conventional
screening (1) at thresholds 1:300 and 1:600,
and (2) at current and improved screening
sensitivity.
Outcomes: Detection of trisomy 21, rate of
procedure-related miscarriage, costs
With cfDNA screening as a first-line test, live
birth prevalence of Down syndrome was
5.10/000 compared with 7.90/000 with current
screening (combined first trimester
screening or second trimester screening).
Rates of procedure-related miscarriage
were lower than with current screening (0.02
vs 0.06%).
Study assumed
that cfDNA
testing has a
sensitivity of
99.3% and a
specificity of
99.84% for
trisomy 21 (Neyt
et al 2014)
33
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Kagan et
al 2015b)
Cohort
study
III-2 675,332 Aim: to examine the screening performance
of a trisomy 21 screening strategy based on
maternal age, cFTS and cfDNA testing as
well as the combinations maternal age and
cfDNA and FTS and cfDNA.
Setting: Germany
Population: all births in 2012
Methods: a model-based approach was
used to evaluate all births together with the
percentage of euploid and trisomic
pregnancies. Detection rates (DR), false
positive rates (FPR), the costs of different
screening strategies for trisomy 21 and
combinations of these strategies were
compared. The number of fetuses with
trisomy 21 at 12+0 weeks of gestation was
estimated based on maternal age
distribution.
Outcomes: Detection of trisomy 21 and
costs
Screening based on FTS (1:250) resulted in a
detection rate (DR) of 92.2% and a false
positive rate (FPR) of 8.0%.
Screening based on cfDNA resulted in a DR
of 99.9% and a FPR of 0.1%. If a 3% fail rate
requiring subsequent invasive testing was
postulated, the total FPR was 3.1% and the
DR remained the same.
When maternal age was combined with
cfDNA (ie testing only offered to women
over 30 years), this resulted in a DR of 85.2%
and a FPR of 1.7%.
Estimates were
based on a
detection rate
of 99.9% and a
false positive
rate of 0.1%
34
Trisomy 21 and other chromosomal anomalies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Kagan et
al 2015a)
Cohort
study
III-2 21,052 Aim: To examine cFTS, cfDNA testing and a
two-step policy that combines FTS and
cfDNA in screening for aneuploidy.
Setting: Germany
Population: pregnancies where cFTS was
performed
Methods: The following screening policies
were examined: cfDNA or FTS with sum risk
cut-offs of 1 in 50 and 1 in 250 in all patients
or a two-step-policy with FTS in all patients
followed by cfDNA in the intermediate sum
risk group. For the intermediate risk group,
sum risk cut-offs of 1 in 50 and 1 in 1000 and
1 in 150 and 1 in 500 were used.
Outcomes: detection of all aneuploidies
FTS with a sum risk cut-off of 1:50 and 1:250
detects 81% and 91% of all aneuploidies.
cfDNA in all cases detects 87.7% of all
aneuploidies.
Detection rates using FTS 1:250 were trisomy
21: 91.3%; trisomy 18: 97.1%; trisomy 13:
92.3%; sex chromosome aneuploidies: 80.0%;
atypical aneuploidies: 87.0%, with invasive
testing in 9.5%.
For cfDNA alone, detection rates were
trisomy 21: 99.2%; trisomy 18: 97.1%; trisomy
13: 92.2%; sex chromosome aneuploidies:
100.0%; atypical aneuploidies: 0%, with
invasive testing in 6.9%
Study assumed
that cfDNA
detects 99%,
98%, 90% and
99% of cases
with trisomy 21,
18, 13 and sex
chromosomal
anomalies and
that the false-
positive rate is
0.5 %.
(Lichtenbel
t et al 2015)
Cohort
study
III-2 25,057 Aim: to determine what percentage of fetal
chromosomal anomalies remains
undetected when first trimester combined
testing is replaced by non-invasive prenatal
testing for trisomies 13, 18, and 21. We
focused on the added clinical value of
nuchal translucency (NT) measurement.
Setting: The Netherlands
Population: singleton pregnancies in which
first trimester combined testing was
performed
Methods: Fetal karyotype, ultrasound
findings and pregnancy outcome of all
pregnancies with an NT measurement
>3.5mm were retrospectively collected.
Two hundred twenty-five fetuses (0.9 %) had
an NT >3.5mm. In 24 of these pregnancies, a
chromosomal anomaly other than trisomy
13, 18, or 21 was detected. Eleven resulted
in fetal demise, and ten showed fetal
ultrasound anomalies. In three fetuses with
normal ultrasound findings, a chromosomal
anomaly was detected, of which one was a
triple X.
In 3 of 25,057 pregnancies (0.01%), non-
invasive prenatal testing and fetal
ultrasound would have missed a
chromosomal anomaly that would have
been identified by NT measurement.
35
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Petersen
et al 2014)
Cohort
study
III-2 193,638 Aim: to determine the risk of missing other
abnormal karyotypes of probable
phenotypic significance by cfDNA testing.
Setting: Denmark
Population: singleton pregnancies booked
for combined first trimester screening over a
4-year period
Methods: Data concerning maternal
demographics, cFTS and prenatal or
postnatal karyotypes were collected from
the Danish Fetal Medicine database.
Karyotypes were classified according to
whether the chromosomal anomaly would
have been detected by cfDNA testing and
whether it was likely to affect phenotype.
10,205 (5.3%) pregnancies had cytogenetic
or molecular analysis performed. Of these,
1,122 (11.0%) had an abnormal karyotype,
of which 262 (23.4%) would have been
missed by CFDNA TESTING, but would
probably have been clinically significant.
The prevalence of such 'atypical abnormal
karyotypes' was increased in women over 45
years of age, in pregnancies with increased
nuchal translucency (NT) thickness (> 3.5
mm), with abnormal levels of free beta-
human chorionic gonadotropin (<0.2 or >
5.0 multiples of the median [MoM]) or
pregnancy-associated plasma protein-
A<0.2 MoM. One or more of these factors
was present in 3% of women, and the
prevalence of atypical abnormal
karyotypes in this high-risk cohort was 1.6%.
Study assumed
that cfDNA
testing would
have 100%
sensitivity for
trisomies 21, 18
and 13 and sex
chromosome
aneuploidy.
36
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Susman et
al 2010)
Cohort
study
III-2 143,051 Aim: To compare the number and types of
chromosome anomalies prenatally
diagnosed and the number of invasive
procedures between current prenatal
testing pathways (a combination of first or
second trimester screening plus ultrasound
and/or diagnostic testing) and a pathway
where cfDNA testing replaces Down
syndrome screening tests.
Setting: Victoria, Australia
Population: women participating in prenatal
diagnostic testing
Methods: Numbers and types of
chromosome anomalies for each referral
category were extracted from prenatal
diagnostic testing reports routinely collected
in Victoria, Australia, in 2006 and 2007. These
data were then applied to the proposed
implementation strategy.
If cfDNA testing for Down syndrome had
replaced Down syndrome screening tests in
2006 and 2007, in Victoria, there would have
been 25 (7%) additional Down syndrome
diagnosed, a 28% reduction in detection of
chromosomal anomalies. Specifically, 56%
non-Down syndrome chromosome
anomalies would no longer detected
(including trisomy 13, trisomy 18, sex
chromosome anomalies, balanced and
unbalanced rearrangements, polyploidy,
and mosaic results).
With the inclusion of trisomy 13, trisomy 18,
and sex chromosome aneuploidy in the
cfDNA panel, the number of missed
anomalies would decrease to 11%.
There would have been 6,896 (84%) fewer
invasive procedures with cfDNA testing for
Down syndrome; 83% fewer with an
aneuploidy panel.
37
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Syngelaki
et al 2014)
Cohort
study
III-2 74,561
(screen)
14,684
(karyo-
type)
Aim: To estimate the proportion of other
chromosomal anomalies that could be
missed if combined screening was replaced
by cfDNA testing as the method of
screening for trisomies 21, 18 and 13.
Setting: United Kingdom
Population: singleton pregnancies
undergoing CVS following screening for
trisomies 21, 18 and 13 by the combination
of maternal age, fetal NT and FHR and
maternal serum-free β-hCG and PAPP-A at
11–13 weeks’ gestation
Methods: The prevalence of trisomies 21, 18
or 13, sex chromosome aneuploidies,
triploidy and other chromosomal anomalies
was examined in pregnancies undergoing
first-trimester combined screening and CVS.
Outcomes: Detection of trisomies 21, 18 and
13, sex chromosome aneuploidies, triploidy
and other chromosomal anomalies
A policy of universal screening by cfDNA
testing for trisomies 21, 18 and 13 would lead
to an invasive testing rate of about 1% and
a detection rate of 98.6% for trisomy 21 and
95.7% for trisomies 18 and 13, but no
detection of sex chromosome aneuploidies,
triploidies or other anomalies at high risk of
adverse outcome. The rate of invasive
testing would be 0.9% and the rate of no
result 2%.
Current combined screening with invasive
testing at risk ≥1:100 would detect 87% of
trsiomy 21, 91.8% of trisomies 13 and 18,
86.0% of monosomy X, 8.1% of other sex
chromosome aneuploidies, 89.3% of triploidy
and 13.0% of other high-risk outcome, with
an invasive test rate of 2.6%.
Estimates based
on cfDNA
detection rates
of 99.0% for
trisomy 21, 96.8%
for trisomy 18,
92.1% for trisomy
13 and a false
positive rate of
0.2%
38
Modelling studies
Trisomy 21 only
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Mersy et al
2015)
Modelling
study
— 100,000 Aim: to conduct a quantitative analysis of
different cfDNA testing strategies.
Setting: The Netherlands
Population: Theoretical cohort of pregnant
women
Methods: Decision trees were created to
illustrate all plausible alternatives in five
screening programmes: classical screening
by the first-trimester combined test (FCT),
pre-selection of high-risk women prior to
cfDNA by the FCT, cfDNA as the first
screening test at 10 weeks and at 13 weeks,
and the simultaneous conductance of
cfDNA and the FCT.
Outcomes: Detection of trisomy 21, rates of
amniocentesis and procedure-related fetal
loss.
cfDNA as the first screening test detects
almost all fetal Down syndrome cases (87.5%
at 10 weeks, 82.5% at 13 weeks compared
to 78.5% with classical first trimester
screening).
Rates of fetal loss due to amniocentesis
complications are lower (n=2 at 10 weeks or
13 weeks versus 25 with classical first
trimester screening) as fewer women
undergo amniocentesis (n=234 vs 4,056).
Model assumed
a sensitivity of
99.6% and
specificity of
99.9% for cfDNA
testing for
trisomy 21 in
high- and low-
risk pregnancies
and a sensitivity
of 89% and
specificity of
95.4% for cFTS.
39
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Morris et al
2014)
Modelling
study
— 10,000 Aim: To investigate the costs and outcomes
of CFDNA TESTING for Down syndrome (DS)
as first- and second-line testing compared
with combined first trimester screening.
Setting: United Kingdom
Population: Cohort of hypothetical pregnant
women
Methods: We used a pre-existing model to
evaluate the costs and outcomes
associated with CFDNA TESTING compared
with the current DS screening programme.
Model inputs were taken from published
sources.
Outcomes: The main outcome measures
were number of DS cases detected, number
of procedure-related miscarriages and total
cost.
As first-line testing, cfDNA testing detects
more trisomy 21 cases (16.49 vs 13.24),
reduces rates of amniocentesis (22.03 vs
160.59), has fewer procedure-related
miscarriages (0.11 vs 0.8), and is more
expensive than current screening (£449,000
vs £279,000 for 10,000 women at a cost of
£50 per cfDNA). When cfDNA uptake
increases, cfDNA detects more trisomy 21
cases with a small increase in procedure-
related miscarriages and costs.
40
Trisomy 21 and other chromosomal anomalies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Kaimal et
al 2015)
Modelling
study
— — Aim: To use a decision-analytic model to
assess a comprehensive set of outcomes of
prenatal genetic testing strategies among
women of varying ages.
Setting: United States
Population: theoretical cohort of women
desiring screening
Methods: We assessed outcomes of six
testing strategies incorporating diagnostic
testing with chromosomal microarray,
multiple marker screening, cell-free DNA
screening, and nuchal translucency
screening alone, in combination, or in
sequence.
Outcomes: prenatal detection or birth of a
neonate with a significant chromosomal
anomaly and diagnostic procedures
performed. Other outcomes included
maternal quality-adjusted life-years and
costs. Sensitivity analyses were conducted
to examine the robustness of the findings.
When considering all detectable
chromosomal anomalies as well as patient
preferences and baseline risks, multiple
marker screening with the option for
diagnostic testing for screen positive results is
the most effective (highest quality-adjusted
life years) at ages 20–38 years. At age 40
years and older, cfDNA as a primary screen
becomes optimal and is cost-effective.
Potential conflict
of interest
41
1.6 Cell-free DNA combined with cFTS
Prospective cohort studies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2013)
Cohort III-2 1,005 Aim: To explore the feasibility of routine
maternal blood cell-free (cf) DNA testing in
screening for trisomies 21, 18 and 13 at
10 weeks gestation.
Setting: United Kingdom
Population: women with singleton
pregnancy and live fetus with CRL 32-45mm.
Median maternal age was 36.7 (range, 20-
49) years.
Methods: women were screened for
trisomies 21, 18 and 13 with blood taken for
maternal serum tests from cFTS and CFDNA
TESTING at 10 weeks and ultrasound
conducted at 12 weeks. Patient-specific risk
was assessed based on results of cFTS tests,
maternal age and history of trisomic
pregnancy.
Outcomes: Detection of trisomies 21, 18 and
13
In 11 cases the risk score for trisomy 21 and in
five cases that for trisomy 18 was >99%, in
one the risk for trisomy 13 was 34% and in
968 the risk for each of the three trisomies
was <0.01%.
The suspected trisomies were confirmed by
karyotyping after CVS, except in one case
of trisomy 18 in which the karyotype was
normal.
Both cfDNA and combined testing detected
all trisomies, but the estimated false-positive
rates (FPR) were 0.1% and 3.4%, respectively.
Risks for trisomies were provided for 957
(95.2%) cases and in 98.0% these were
available within 14 days from sampling.
In 48 (4.8%) cases no result was provided
due to problems with delivery to the
laboratory, low fetal fraction or assay failure.
Repeat sampling was performed in 40 cases
and a result obtained in 27 (67.5%) of these.
42
Study ref Design LoE N Aim, setting, population, methods Results Comments
(McLennan
et al 2016)
Cohort III-2 5,267 Aim: To assess the implementation of CFDNA
TESTING into clinical practice utilising both
first- and second-line screening models.
Setting: Metropolitan private practices in
Australia
Population: Singleton pregnancies in a
mixed risk population
Methods: cfDNA testing was offered as a
first-line screen, ideally followed by
combined first-trimester screening (cFTS), or
as a second-line test following cFTS,
particularly in those with a calculated risk
between 1:50 and 1:1000.
Outcomes: Detection of trisomies 21, 18 13,
sex chromosome aneuploidies and other
anomalies
cfDNA screening was performed in 5,267
women and as a first-line screening method
in 3,359 (63.8%). Detection rates were 100%
for trisomies 21 and 13 and 88% for
trisomy 18. Of cases with known karyotypes,
the positive predictive value (PPV) of the
test was highest for trisomy 21 (97.7%) and
lowest for monosomy X (25%).
Ultrasound detection of fetal structural
anomaly resulted in the detection of five
additional chromosome anomalies, two of
which had high-risk cFTS results.
For all chromosomal anomalies, cfDNA
alone detected 93.4%, cfDNA in a second-
line model detected 81.8% and cFTS alone
detected 65.9% (P < 0.005).
If women had only had cFTS, the rate of
invasive procedures would have been 5.5%
higher (p<0.0001).
Given the false-positive rate for all
aneuploidies, cfDNA is an advanced
screening test, rather than a diagnostic test.
Study
population may
not be
generalisable to
the Australian
obstetric
community as
women were
predominantly
older,
Caucasian and
from higher
socioeconomic
groups
43
Retrospective cohort studies
Trisomy 21 only
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Conner et
al 2015)
Cohort
Study
III-2 35,780 Aim: To evaluate the performance and cost
efficacy of different first-trimester second-
line screening strategies based on an initial
analysis of biochemical markers.
Setting: Swedish National Quality Register for
prenatal diagnosis.
Population: women with singleton
pregnancies.
Methods: Serum values from first trimester
biochemistry were re-analyzed in a second-
line approach. For risks between 1:40 and
1:1000, risk estimates from nuchal
translucency measurements were added
and outcomes were compared using either
a final cut-off risk of 1:200 to proceed with
invasive testing or offering non-invasive
prenatal testing. The costs of detecting one
case of aneuploidy were compared.
Outcomes: Detection of trisomies 21, 18 and
13 (only trisomy 21 reported for cfDNA).
Offering cfDNA testing to the intermediate
risk group (double serum test risk between
1:40 and 1:1,000) would result in a trisomy 21
detection rate of 98% (compared to 87% for
combined screening and second-line
screening using nuchal translucency as a
second-tier test), but the cost to detect one
case of trisomy 21 would be 83% higher than
the cost associated with traditional
combined screening.
44
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gyselaers
et al 2015)
Cohort
study
III-2 99,619 Aim: To evaluate costs and benefits of
different scenarios for second-line cfDNA
screening.
Setting: Belgium
Population: Pregnancies screened by
combined first trimester screening (78.5%) or
second trimester screening (21.5%) in 2011
Methods: Data from the Belgian National
Institute for Health and Disability Insurance
and the Study Centre for Perinatal
Epidemiology were used in modeled
calculations of medical and economic
impact of cfDNA testing after prior
conventional screening (1) at thresholds
1:300 and 1:600, and (2) at current and
improved screening sensitivity.
Outcomes: Detection of trisomy 21, rate of
procedure-related miscarriage, costs
Second-line cfDNA screening under current
screening conditions would maintain today's
7.90/000 live birth prevalence of Down
syndrome (LBPD) at an 11% reduction of
overall short-term costs. Lowering the
screening threshold to 1:600 or increasing
sensitivity by 10% would reduce LBPD to
70/000 at a maximum 3% increase of overall
short-term costs.
Rates of procedure-related miscarriage
were lower with cfDNA than with current
screening (0.03 vs 0.06%) with a risk threshold
of 1:300 or 1:600.
The study
assumed that
cfDNA testing
has a sensitivity
of 99.3% and a
specificity of
99.84% for
trisomy 21 (Neyt
et al 2014)
45
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Kagan et
al 2015b)
Cohort
study
III-2 675,332 Aim: to examine the screening performance
of a trisomy 21 screening strategy based on
maternal age, first trimester screening (FTS)
and cfDNA testing as well as the
combinations maternal age and cfDNA and
FTS and cfDNA.
Setting: Germany
Population: all births in 2012
Methods: a model-based approach was
used to evaluate all births together with the
percentage of euploid and trisomic
pregnancies. Detection rates (DR), false
positive rates (FPR), the costs of different
screening strategies for trisomy 21 and
combinations of these strategies were
compared. The number of fetuses with
trisomy 21 at 12+0 weeks of gestation was
estimated based on maternal age
distribution.
Outcomes: Detection of trisomy 21 and
costs
Screening based on FTS (1:250) resulted in a
detection rate (DR) of 92.2 and a false
positive rate (FPR) of 8.0.
When maternal age was combined with
cfDNA (ie only offered to women over a
certain age); if a cut-off of 30 years was
used, this resulted in a DR of 85.2 and a FPR
of 1.7.
If primary screening consisted of FTS with
cfDNA testing when the risk was between
1:10 and 1:1000, the detection rate was 96.7
and the false positive rate was 1.2.
Estimates were
based on a
detection rate
of 99.9% and a
false positive
rate of 0.1%
46
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Maxwell et
al 2016)
Cohort
study
III-2 90,352 Aim: To provide data on how screen-
positive and detection rates of first trimester
prenatal screening for fetal Down syndrome
vary with changes in the risk cut-off and
maternal age to inform contingency criteria
for publicly funded noninvasive prenatal
testing.
Setting: Australia
Population: all women attending for first
trimester fetal aneuploidy screening in
Western Australia between 2005 and 2009
Methods: First trimester screening and
diagnostic data were collected and were
linked to pregnancy outcomes, including
data from the Midwives' Notification System
and the Western Australian Registry of
Developmental Anomalies.
Outcomes: Prevalence of trisomy 21 and
performance of risk cut-offs
The current screening risk cut-off of 1:300 has
screen-positive and detection rates of 3.5%
and 82%. The screen-positive rate increases
by 0.7-0.8% for each 100 point change in
risk, up to 19.2% at 1:2500 (96% detection
rate). Including all women >35 years as
screen positive would increase the screen-
positive rate and detection rates to 30.2%
and 97.2%.
Variation in screening risk cut-off and the
use of maternal age to assess eligibility for
noninvasive testing could significantly
impact the demand for, and cost of, the
test. A second-line first trimester screening
approach for risk assessment is superior to
the use of a combination of screening and
maternal age alone.
47
Study ref Design LoE N Aim, setting, population, methods Results Comments
(O'Leary et
al 2013)
Cohort
study
III-2 32,478 Aim: To analyse the cost-effectiveness and
performance of cfDNA testing for high-risk
pregnancies following first-trimester
screening compared with current practice.
Setting: West Australia, Australia
Population: singleton pregnancies screened
between January 2005 and December 2006
Methods: A decision-tree analysis was used
to compare the costs and benefits of
current practice of first-trimester screening
with a testing pathway incorporating cfDNA
testing for women with combined first
trimester screening risk of 1:300. We applied
the model, adding Medicare rebate data
as a measure of public health system costs.
The analyses reflect the actual uptake of
screening and diagnostic testing and
pregnancy outcomes in this cohort.
Outcomes: Detection of trisomy 21, numbers
of invasive tests and procedure-related
miscarriages, costs
If cfDNA testing was adopted by all women
identified as high risk by cFTS, up to 7 (2 per
10,000 women) additional trisomy 21 fetuses
could be confirmed.
The introduction of second-line cfDNA
testing would reduce the number of invasive
diagnostic procedures in high-risk women by
88%.
48
Trisomy 21 and other chromosomal anomalies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Kagan et
al 2015a)
Cohort
study
III-2 21,052 Aim: To examine combined first trimester
screening (FTS), cfDNA testing and a two-
step policy that combines FTS and cfDNA in
screening for aneuploidy.
Setting: Germany
Population: pregnancies where FTS was
performed
Methods: The following screening policies
were examined: cfDNA or FTS with sum risk
cut-offs of 1 in 50 and 1 in 250 in all patients
or a two-step-policy with FTS in all patients
followed by cfDNA in the intermediate sum
risk group. For the intermediate risk group,
sum risk cut-offs of 1 in 50 and 1 in 1000 and
1 in 150 and 1 in 500 were used.
Outcomes: detection of all aneuploidies
FTS with a sum risk cut-off of 1:50 and 1:250
detects 81% and 91% of all aneuploidies.
cfDNA in the 2-step approach with sum risk
cut-offs of 1:50 and 1:1000 detects 94% of all
aneuploidies. With sum risk cut-offs of 1:150
and 1:500, the detection rate is 93%.
Detection rates using FTS 1:250 were trisomy
21: 91.3%; trisomy 18: 97.1%; trisomy 13:
92.3%; sex chromosome aneuploidies: 80.0%;
atypical aneuploidies: 87.0%, with invasive
testing in 9.5%.
Using a 2-step approach with cfDNA for
1:50–1:1,000, detection rates were trisomy
21: 97.6%; trisomy 18: 100.0%; trisomy 13:
92.3%; sex chromosome aneuploidies: 93.3%;
atypical aneuploidies: 69.6%, with invasive
testing in 4.1%.
Using a 2-step approach with cfDNA for
1:150–1:500, detection rates were trisomy 21:
95.3%; trisomy 18: 97.1%; trisomy 13: 92.3%;
sex chromosome aneuploidies: 80.0%;
atypical aneuploidies: 87.0%, with invasive
testing in 6.9%.
Study assumed
that CFDNA
TESTING detects
99%, 98%, 90%
and 99% of
cases with
trisomy 21, 18, 13
and sex
chromosomal
anomalies and
that the false-
positive rate is
0.5 %.
49
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Khalil et al
2015)
Cohort
study
III-2 5,306 Aim: to investigate aneuploidy detection
using an approach based on nuchal
translucency (NT) and cfDNA testing.
Setting: United Kingdom
Population: Pregnancies identified as high-
risk by combined first trimester screening
Methods: analysis of NT measurements and
chorionic villus samples (CVS) tested for full
karyotype to estimate the potential impact
of:
• current practice, where high-risk women
have a CVS
• relying entirely on cfDNA to replace CVS
for all high-risk women or
• using cfDNA as the main method of
prenatal screening, with CVS reserved
for increased NT thickness and a family
history of chromsomal anomalies
Outcomes: Detection of aneuploidies, rates
of invasive tests and procedure-related
miscarriage.
A policy of relying solely on cfDNA as a
second-tier screen for women identified as
high-risk by combined first trimester
screening would have led to the diagnosis
of 88.9% of clinically significant anomalies
and avoid miscarriage in 98% of
pregnancies compared to CVS for all.
A strategy whereby cfDNA is the main
second-tier test, with CVS reserved for cases
with NT ≥3.0 mm, would require CVS in 21.7%
of cases, identify 94.8% of significant
anomalies and avoid miscarriage in 77%
pregnancies compared to CVS for all.
Study assumed
that trisomies 21,
18 and 13, 45X,
other sex
chromosome
aneupleudies,
triploidy and
tetraploidy were
detectable by
cfDNA testing
and assumed a
0% failure rate.
Potential conflict
of interest
50
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Maxwell et
al 2015)
Cohort
study
III-2 1,488 Aim To describe the potential impact of
using cfDNA testing as a second-tier test, on
the diagnosis and outcomes of pregnancies
identified as high risk through first trimester
screening (FTS) in a cohort of real
pregnancies.
Setting: Australia
Population:
Methods: Western Australian FTS and
diagnostic data (2007-2009) were linked to
pregnancy outcomes. Karyotype results
from invasive prenatal testing in high-risk
women were analysed.
Outcomes: abnormal results that would not
be detected by cfDNA testing, assuming a
panel of trisomy 21/18/13 and sex
chromosome aneuploidies, and the
likelihood of diagnosis in a screening model
using CFDNA as a second-tier test.
Abnormal karyotype results were reported in
224 (15%) women with high-risk pregnancies
having invasive diagnostic testing. cfDNA
testing potentially would have identified
85%. The 33 anomalies unidentifiable by
CFDNA were triploidies (n=7, 21%), balanced
(n=8, 24%) and unbalanced rearrangements
(n=10, 30%) and level III mosaicisms (n=8,
24%).
For conditions not identifiable by CFDNA,
fetal sonographic appearance was likely to
have led to invasive testing for 10 of 17 (59%)
pathogenic anomalies.
A screening model with cfDNA as a second-
tier for high-risk pregnancies would be
unlikely to have changed the outcome for
the majority of pregnancies. Optimising the
diagnosis of rare pathogenic anomalies
requires clear indicators for invasive testing
over cfDNA.
Don’t have full
text
51
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Syngelaki
et al 2014)
Cohort
study
III-2 14,684 Aim: To estimate the proportion of other
chromosomal anomalies that could be
missed if combined screening was replaced
by cell-free (cf) DNA testing as the method
of screening for trisomies 21, 18 and 13.
Setting: United Kingdom
Population: singleton pregnancies
undergoing CVS following screening for
trisomies 21, 18 and 13 by the combination
of maternal age, fetal NT and FHR and
maternal serum-free β-hCG and PAPP-A at
11–13 weeks’ gestation
Methods: The prevalence of trisomies 21, 18
or 13, sex chromosome aneuploidies,
triploidy and other chromosomal anomalies
was examined in pregnancies undergoing
first-trimester combined screening and
chorionic villus sampling (CVS).
Outcomes: Detection of trisomies 21, 18 and
13, sex chromosome aneuploidies, triploidy
and other chromosomal anomalies
Combined screening followed by CVS for
risk >1:10 and cfDNA testing for risk 1:11-
1:2,500 could detect 97% of trisomy 21 and
98% of trisomies 18 and 13. Additionally, 86%
of monosomy X, half of 47,XXY, 47,XYY or
47,XXX, half of other chromosomal
anomalies and one third of triploidies that
are currently detected by combined
screening and CVS for risk>1:100, could be
detected.
Screening by cfDNA testing, contingent on
results of combined testing, improves
detection of trisomies, but misses a few of
the other chromosomal anomalies detected
by screening with the combined test.
Current combined screening with invasive
testing at risk ≥1:100 would detect 87% of
trsiomy 21, 91.8% of trisomies 13 and 18,
86.0% of monosomy X, 8.1% of other sex
chromosome aneuploidies, 89.3% of triploidy
and 13.0% of other high-risk outcome, with
an invasive test rate of 2.6%.
Estimates based
on cfDNA
detection rates
of 99.0% for
trisomy 21, 96.8%
for trisomy 18,
92.1% for trisomy
13 and a false
positive rate of
0.2%
52
Modelling studies
Trisomy 21 only
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Mersy et al
2015)
Modelling
study
— 100,000 Aim: to conduct a quantitative analysis of
different CFDNA implementation strategies.
Setting: The Netherlands
Population: Theoretical cohort of pregnant
women
Methods: Decision trees were created to
illustrate all plausible alternatives in five
screening programmes: classical screening
by cFTS, pre-selection of high-risk women
(>1:200) prior to cfDNA by the cFTS, cfDNA
as the first screening test at 10 weeks and at
13 weeks, and the simultaneous
conductance of cfDNA and the cFTS.
Outcomes: Detection of trisomy 21, rates of
amniocentesis and procedure-related fetal
loss.
Detection rate for trisomy 21 in the first
trimester was the same for cFTS and cFTS
plus cfDNA (78.5%) but the false positive rate
was lower in the latter (n=4 vs 4,412)
Pre-selection by cFTS prior to cfDNA reduces
the number of amniocenteses to a minimum
(136 vs 234 with cfDNA used as a first-line test
and 4,056 with cFTS) because of a reduction
of false-positive cfDNA results (4 vs 95–96
with cfDNA used as a first-line test).
Model assumed
a sensitivity of
99.6% and
specificity of
99.9% for cfDNA
testing for
trisomy 21 in
high- and low-
risk pregnancies
and a sensitivity
of 89% and
specificity of
95.4% for cFTS.
53
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Morris et al
2014)
Modelling
study
— 10,000 Aim: To investigate the costs and outcomes
of CFDNA TESTING for Down syndrome (DS)
as first- or second-line screening compared
with combined first trimester screening.
Setting: United Kingdom
Population: Cohort of hypothetical pregnant
women
Methods: We used a pre-existing model to
evaluate the costs and outcomes
associated with cfDNA testing compared
with the current trisomy 21 screening
programme. Model inputs were taken from
published sources.
Outcomes: Number of trisomy 21 cases
detected, number of procedure-related
miscarriages and total cost.
At a screening risk cut-off of 1:150 in a
population of 10,000 women, cfDNA as
second-line testing detects slightly fewer
trisomy 21 cases (11.26 vs 13.24), has fewer
procedure-related miscarriages (0.06 vs 0.8),
and costs the same as current screening
(around UK280,000) at a cost of 500 per
cfDNA.
54
Trisomy 21 and other chromosomal anomalies
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Kaimal et
al 2015)
Modelling
study
— — Aim: To use a decision-analytic model to
assess a comprehensive set of outcomes of
prenatal genetic testing strategies among
women of varying ages.
Setting: United States
Population: theoretical cohort of women
desiring screening
Methods: We assessed outcomes of six
testing strategies incorporating diagnostic
testing with chromosomal microarray,
multiple marker screening, cell-free DNA
screening, and nuchal translucency
screening alone, in combination, or in
sequence.
Outcomes: Clinical outcomes included
prenatal detection or birth of a neonate
with a significant chromosomal anomaly
and diagnostic procedures performed.
Other outcomes included maternal quality-
adjusted life-years and costs. Sensitivity
analyses were conducted to examine the
robustness of the findings.
At all ages assessed, screening strategies
starting with multiple marker screening
offered the highest detection rate when all
chromosomal anomalies were considered
Incorporating cfDNA as an optional
secondary screen decreased the number of
diagnostic procedures, but also decreased
the number of anomalies diagnosed
prenatally, resulting in a similar number of
procedures per case diagnosed at age
30 years; the option of secondary cfDNA
screening becomes more favorable at older
ages.
Potential conflict
of interest
55
1.7 Impact of cell-free fetal DNA testing on screening practices and invasive procedures
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Chan et al
2015)
Historical
control
III-3 Aim: to evaluate the uptake of non-invasive
cell-free fetal DNA screening test (NIDT) after
a high-risk screening result for trisomy 21
Setting: Hong Kong
Population: Chinese women who had a
high-risk (term risk >1:250) first-trimester or
second-trimester screening test at three
public hospitals.
Measurements: Association between
maternal and pregnancy characteristics on
women's test choice was assessed after
adjusting for confounding factors
Outcomes: rate of declining further testing
and obstetric and maternal factors
impacting on patient's selection of testing
options.
Compared with the pre-cfDNA period, the
availability of cfDNA resulted in a 45%
(P<0.001) reduction in the rate of refusal for
further testing and a decrease from 92.2% to
66.7% in the use of invasive diagnostic test
after a positive screening test.
56
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Chetty et
al 2013)
Historical
control
III-3 1,036 Aim: to investigate how the introduction of
cfDNA testing impacted women's testing
choices following a positive prenatal
screening (PNS) result.
Setting: United States
Population: Women with a positive prenatal
screening test result (first and/or trimester
serum analytes and nuchal translucency
ultrasound)
Method: Women were offered cfDNA or
invasive prenatal diagnosis.
Outcomes: Rates of invasive testing and
declining follow-up were compared with
testing decisions the prior year. Differences
were compared using t-test and chi-square.
Multivariable logistic regression was
performed to identify predictors of test
choice.
Year before introduction: 638 screen positive
patients were seen: 301 (47.2%) had invasive
testing and 337 (52.8%) declined.
Year post introduction: 156 (39.2%)
underwent invasive testing, 157 (39.4%) had
cfDNA and 84 (21.1%) declined further
testing.
The rate of invasive testing declined
significantly (p=0.012). Moreover, fewer
women declined follow-up testing after
introduction of cfDNA, 21.2% versus 52.8%,
p<0.001.
(Friel et al
2014)
Historical
control
III-3 982 Aim: to determine the impact of cfDNA on
the uptake of first trimester screening (FTS)
and invasive genetic testing.
Setting: United States
Population: women referred for advanced
maternal age or abnormal screening.
Method: Patients who presented before
clinical introduction of cfDNA were
compared with patients who presented
after its introduction.
Outcomes: rates of FTS and invasive genetic
testing
In patients referred between 14 and 22
weeks gestational age, invasive genetic
testing was significantly reduced following
the introduction of cfDNA (35.4 vs. 17.9%,
p<0.05).
For patients referred at <14 weeks
gestational age, FTS was significantly
reduced with cfDNA introduction (89.1 vs.
59.1%, p<0.05); however, invasive genetic
testing was not significantly different (20.0 vs.
14.0%, p>0.05).
57
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Hasegawa
et al 2015)
Historical
control
III-3 1,247 Aim: To clarify the trends in the use of the
prenatal diagnosis of and screening for
aneuploidy after cfDNA was made
available.
Setting: Japan
Population: consecutive pregnant women
who visited our hospital for maternal
checkups and delivery.
Methods: Subjects were divided into those
who desired a prenatal diagnosis or
screening before the availability of cfDNA
and those who did after the availability of
cfDNA.
Outcomes: frequencies of various prenatal
diagnosis and screening procedures.
Among women who attended before
cfDNA was available (n=544), 16.2 %
received prenatal screening or diagnosis.
Among women who attended after cfDNA
was available, 27.5% considered
undergoing a prenatal diagnosis or
screening before genetic counseling and
24.0 % ultimately received a prenatal
diagnosis or screening following genetic
counseling. Of these patients, 7.7 %
underwent cfDNA. First trimester ultrasound
screening for chromosomal anomalies was
unlikely to be selected (from 12.9 to 10.5 %,
p=0.212), although the rate of
amniocentesis significantly increased after
genetic counseling (from 1.5 to 3.7 %,
p=0.021).
58
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Larion et al
2014b)
Historical
control
III-3 15,418
tests
Aim: To describe the changes over a 9-year
period in the number and rate of diagnostic
testing after the introduction of the
combined first-trimester screen and
subsequent cfDNA testing.
Setting: United States
Population: women participating in prenatal
screening at a maternal-fetal medicine
group practice.
Methods: The number of prenatal screening
and diagnostic tests was recorded over a 9-
year period from billing records. Three time
intervals were considered: 20 months before
a combined first-trimester screen was
offered; 72 months after a combined first-
trimester screen was offered; and 16 months
after cfDNA testing introduction. Prenatal
testing was compared per year, per time
interval, and per 100 morphologic
ultrasonograms to account for fluctuations
in patient number.
Outcomes: rates of combined first trimester
screening, CVS and amniocentesis
Combined first-trimester screen peaked at
1,836 in 2009-2010 but declined by 48.1%
after cfDNA testing was introduced.
Combined first-trimester screen per 100
morphologic ultrasonograms also
significantly decreased (P<0.05) after cfDNA
testing introduction.
CVS peaked after combined first-trimester
screen introduction in 2007-2008 with 100
procedures, representing an 81.8% increase
from prefirst-trimester screen. After the
introduction of cfDNA, CVS declined by
68.6% during 2012-2013. CVS per 100
morphologic ultrasonograms followed the
same trend.
Amniocentesis declined every year of the
study period (78.8% overall), including 60.3%
after combined first-trimester screen and a
further 46.7% after noninvasive prenatal
testing. Monthly amniocentesis procedures
per 100 morphologic ultrasonograms
significantly decreased (P<.05) after
introduction of a combined first-trimester
screen and cfDNA.
59
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Larion et al
2014a)
Historical
control
III-3 9,287
procedu
res
Aim: to assess cfDNA uptake and
subsequent changes in the utilization of first-
trimester screen (FTS), chorionic villus
sampling (CVS), and amniocentesis.
Setting: United States
Population: singleton pregnancies of women
who desired prenatal screening and
diagnostic testing in a single referral center
Method: Monthly numbers of cfDNA (in high-
risk patients), FTS, CVS, and amniocentesis
were compared between a 35-month
baseline period (April 2009 through February
2012) before introduction of cfDNA, and the
initial 16 months following cfDNA
introduction divided in 4-month quarters
beginning in March 2012 through June 2013.
Outcomes: rates of FTS, CVS and
amniocentesis
A total of 1,265 cfDNA, 6,637 FTS, 251 CVS,
and 1,134 amniocentesis were recorded
over the 51-month study period in. cfDNA
became the predominant screening
method by the second quarter following its
introduction, increasing by 55.0% over the
course of the study period.
Total first-trimester risk assessments
(cfDNA+FTS) were not statistically different
following cfDNA (P=0.312), but average
monthly FTS procedures significantly
decreased following cfDNA introduction,
decreasing by 48.7% over the course of the
study period.
Average monthly CVS and amniocentesis
procedures significantly decreased
following cfDNA introduction, representing a
77.2% and 52.5% decrease in testing,
respectively. Screening and testing per 100
morphological ultrasounds followed a similar
trend.
60
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Larion et al
2015)
Historical
control
III-3 10,125 Aim: To report changes in the use of cFTS in
patients classified as high and low risk for
fetal aneuploidy, including after
introduction of cfDNA testing.
Setting: United States
Population: first trimester screening tests in
high and low-risk women
Methods: A prospectively collected
database was reviewed to investigate
changes in cFTS use before and after
American College of Obstetricians and
Gynecologists recommended that all
patients be offered aneuploidy screening
(2007), and after cfDNA introduction.
Statistical significance was defined as
P<0.05.
Outcomes: numbers of FTSs per 100
morphological ultrasound examinations.
In the 88-month study period, there were
2,962 FTSs in high-risk patients and 7,163 in
low-risk patients. The total number of FTSs
performed per 100 morphological
ultrasound examinations significantly
increased after the ACOG
recommendation and significantly
decreased after cfDNA introduction.
In high-risk patients, the total number of FTSs
performed per 100 morphological
ultrasound examinations significantly
increased after the ACOG
recommendation but significantly
decreased after cfDNA introduction.
In contrast, in low-risk patients, the total
number of FTSs performed per 100
morphological ultrasound examinations
significantly increased after the ACOG
recommendation but was not statistically
different after cfDNA introduction.
61
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Li et al
2016)
Historical
control
III-3 7,536 Aim: to examine changes over a 4-year
period in the number of diagnostic testing
after the introduction ofcfDNA testing.
Setting: China
Population: all consecutive patients with a
singleton pregnancy who received
amniocentesis at 16–22 weeks at a regional
maternal-fetal medicine center
Methods: The rate of cfDNA as an indication
in women who received amniocentesis, and
the number of amniocentesis required for
detection of one case with major
aneuploidy were compared between a 1-
year baseline period before the introduction
of cfDNA, and the 3 years following cfDNA
introduction.
Outcomes: Indications for amniocentesis
and indications for amniocentesis
A total of 7,536 amniocentesis procedures
were performed over the 4-year study
period. During the baseline period of the
year 2011, the number of invasive testing
required for detection of one common
trisomy was 57. During the first 2 years that
cfDNA was offered, cfDNA averaged 1.7%
of the total indications for amniocentesis,
and the required number of invasive testing
decreased to 30. With the increase of the
percentage of cfDNA during the 3rd year,
the required number of invasive testing
further decreased to 26.
After the clinical introduction of cfDNA,
invasive prenatal diagnostic testing had not
decreased at a Chinese prenatal diagnostic
unit, but a remarkably improved detection
rate of major aneuploidies in diagnostic
procedures was observed.
62
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Manegold
-Brauer et
al 2014)
Historical
control
III-3 951 Aim: to describe the current impact of
cfDNA testing on prenatal care.
Setting: Switzerland
Population: women with singleton
pregnancies who presented for first trimester
screening (FTS)
Methods: According to the results of FTS the
women were categorised into three risk
groups: low risk for aneuploidy (<1:300),
intermediate risk (1:300-1:50) and high risk
(>1:50). They were counselled about the
available options for invasive prenatal
testing (IPT) and cfDNA available at the time
of FTS. The nine months before and after the
introduction of cfDNA were evaluated
Outcomes: further testing after FTS.
Since the introduction of cfDNA testing,
there has been an overall increase of 3.6%
of additional prenatal tests including both
IPT and cfDNA testing after FTS (8.5% vs
12.1%, p = 0.068).
In the low risk category this increase
amounted to 4.7% (2.2% vs 6.9%, p <0.149),
whereas in the intermediate risk category
this increase was 10.7% (35.1% vs 45.8%, p =
0.016).
In the high risk category an increase of 1.8%
(55.0% vs 56.8%, p = 0.149) was noted.
In contrast, the overall decrease of IPT was
5.5% (8.8% vs 3.1%, p = 0.001). The decrease
was 1.1% in the low-risk group, 29.4% in the
intermediate-risk group and 16.8% in the
high-risk group.
Since the introduction of cfDNA, the total
number of invasive prenatal procedures
decreased by 67.4% (43 vs 14).
63
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Manegold
-Brauer et
al 2015)
Historical
control
III-3 2,271 Aim: to investigate the algorithm of prenatal
testing before and after the introduction of
cfDNA in a tertiary referral center and to
investigate the influence of cfDNA on the
frequency of invasive procedures.
Setting: Switzerland
Population: singleton pregnancies
presenting for first trimester screening
Method: Retrospective data analysis was
conducted of all singleton pregnancies that
presented for first trimester screening 17
months before and after the introduction of
cfDNA (n = 2271). Women were categorized
into three risk groups: low risk for trisomy 21
(<1:1000), intermediate risk (1:101-1:1000)
and high risk (>1:100).
Outcomes: The choice of diagnostic testing
after FTS.
1,093 (group 1) presented before and 1,178
(group 2) after the introduction of cfDNA.
The rate of high-risk patients was equal in
both groups (14.4 vs. 15.4 %). No differences
were found with regard to invasive testing
(11.6 vs. 11.3 %).
cfDNA was chosen by 3.7% (n=44) in group
2. Of those with cfDNA, 72.7% had a risk
estimate of <1:100, but 90.9% were >35 years
old. The rate of cfDNA among high-risk
patients with a normal ultrasound
examination was 25%.
64
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Palomaki
et al 2015)
Historical
control
III-3 82 lab
surveys
Aim: to determine whether tests for fetal
aneuploidy based on cfDNA in maternal
circulation have had an impact on routine
serum-based screening.
Setting: United States
Population: Pregnant women aged ≥35
years
Methods: We compared results from
laboratory surveys in 2011 and 2014 that
reported types of prenatal serum screening
tests and numbers of tests performed.
Testing records from two prenatal serum
screening laboratories examined temporal
trends in the proportion of screened women
35 years of age and older from 2008 (or
2009) to 2014.
Outcomes: serum screening rates
The survey results available for comparison
showed that 1.7 million women were
screened in 2014, a 5% increase over 2011.
In the two screening laboratories, the
proportion of screened women ≥35 years
increased for several years but then
experienced reductions of 8 and 18% by
mid-2014 when compared with the highest
rates observed.
As of 2014, maternal plasma DNA testing
appears to have had only a minor impact
on serum screening rates in the United
States. Ongoing surveillance has the
potential to determine if, and when, DNA
testing begins to replace serum testing as a
primary screen for trisomy 21 in the United
States.
Behind paywall
65
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Pettit et al
2014)
Historical
control
III-3 206 Aim: To evaluate trends in the use of
invasive diagnostic procedures.
Setting: United States
Population: Women undergoing cfDNA
testing at a large academic center.
Method: cfDNA testing was universally
offered to all high-risk patients as
recommended by ACOG. Women were
also offered invasive diagnostic testing as an
alternative. The study period was compared
to a similar time period before universal offer
of cfDNA testing.
Outcomes: indications for cfDNA testing,
results of aneuploidy screening, ultrasound
examination findings, and CVS or
amniocentesis results
During the study period, 206 patients had
cfDNA testing. Of those, 75% (155/206) were
aged ≥35 years. Of those undergoing cfDNA
testing, 41% had positive aneuploidy
screening and 38% had abnormal
ultrasound findings. Only 7% of the patients
with negative cfDNA testing opted for an
invasive diagnostic procedure compared
with 60% with positive testing (P<0.01).
The rate of invasive procedures decreased
from 5.9% of all visits to the center during a
similar 8-month period in 2010 to 4.1% of all
visits during the study period (P<0.01).
(Platt et al
2014)
Cohort
study
III-2 1,477 Aim: to assess the impact of regional
location on cfDNA testing implementation
and downstream invasive prenatal
procedure use
Setting: United States
Population: Women who underwent cfDNA
Methods: Six different regionally based
centers collected data. Statistical analyses
were performed using the 2-proportion Z-
test.
Outcomes: cfDNA testing indication and
results and invasive prenatal procedure
rates before and after offering cfDNA testing
Advanced maternal age (AMA-only) was
the most frequent indication in five of six
sites (range, 21.8-62.9%)
More invasive procedures were performed
following negative cfDNA testing results
(n=61) than abnormal cfDNA testing results
(n=30).
The overall rate of patients undergoing
invasive procedure after an abnormal
cfDNA testing result was 32.6% (30 of 92).
All six centers reported a decrease in
amniocentesis rates (from –23.6% to –50.0%).
Four of six centers reported a decrease in
rates of CVS (from –14.2% to –65.7%) and 2
centers reported no change.
66
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Poon et al
2015)
Historical
control
III-3 1,069 Aim: To investigate how the introduction of
cfDNA testing influenced women's testing
choices following a positive trisomy 21
screening.
Setting: Hong Kong
Population: Women (largely Chinese) with a
singleton pregnancy and a positive trisomy
21 screening (first trimester combined screen
or second trimester screening depending on
gestational age at presentation).
Methods: With the use of descriptive
statistics and a χ2 test, rates of women
choosing the invasive test and those who
declined further testing were compared
before and after the introduction of CFDNA
TESTING. We also compared demographic
factors with rates of different options
including an invasive test, cfDNA or
‘declined further testing’. Predictors of
accepting cfDNA and an invasive test were
analyzed with multiple logistic regression.
Conventional screening was funded
publicly, but cfDNA was not.
Outcomes: differences in the uptake rates of
invasive prenatal diagnosis (IPD) or no
testing before and after the introduction of
cfDNA and factors affecting choices.
In pre-cfDNA and in years 1 and 2 after the
introduction of cfDNA, 306, 362 and 401
women who screened positive were seen,
respectively.
In year 1 and year 2, 12.6 and 26.7% of
women underwent cfDNA while IPD was
decreased by 16.3 and 25.6%, respectively
(p<0.001). Both chorionic villus sampling and
amniocentesis decreased in year 1, but only
the former in year 2. The rate of declining
further testing was similar before and after
introduction of cfDNA (p = 0.213).
67
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Robson &
Hui 2015)
Historical
control
III-3 Aim: to assess changes in rates of invasive
diagnostic prenatal procedures associated
with combined first trimester screening and
cfDNA
Setting: Australia
Population: invasive procedures claimed
through Medicare from 1994 to 2014
Method: analysis of data from the Medicare
Australia Medical Benefits Scheme (MBS)
database on procedural item numbers
16600 (diagnostic amniocentesis) and 16603
(chorionic villus sampling [CVS] by any
route) for the period 1994 to 2014 inclusive,
by calendar year
Outcomes: changes in rates of invasive
diagnostic tests
Following the introduction of cfDNA, the
number of amniocenteses performed in
Australia fell by 51% between the first
quarter of 2013 and the final quarter of 2014
(1,560 vs 758. OR 0.48; 95% CI: 0.44–0.53; 2 =
282, P<0.005). The total number of CVS fell
by 37% over the same period (767 vs 481. OR
0.63; 95% CI: 0.56–0.70; 2 = 66, P<0.005). This
represents the largest annual decrease in
invasive procedures during the 20-year study
period.
This change has important implications for
training in, and maintenance of, the
procedural skills of amniocentesis and CVS.
(Shah et al
2014)
Historical
control
III-3 500 Aim: To assess the impact of cfDNA testing
on choice of invasive procedures.
Setting: United States
Population: Women with a positive first
trimester screening result.
Method: A retrospective chart review was
performed. Data were collected prior to
(2011) and after (2012) the introduction of
cfDNA.
Outcomes: gestational trimester at positive
screen, whether cfDNA screening was
requested or offered, and any additional
tests pursued
The percentage of participants who chose
not to pursue further testing after a positive
screen decreased significantly between
2011 and 2012, from 44% (110/250) to 32%
(79/250) (p=0.006). Of those participants
who chose to pursue additional testing in
2011, 47% (117/250) chose invasive testing
(either CVS or amniocentesis) and only 29%
chose invasive testing in 2012 (p<0.001).
68
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Tiller et al
2015)
Historical
control
III-3 200 Aim: To prospectively determine the impact
of cfDNA on invasive procedure utilization in
a managed care setting and to elucidate
women's views.
Setting: Southern California
Population: Pregnant women at 10-20
weeks' gestation with high-risk indications for
fetal aneuploidy
Methods: Enrolled patients received routine
prenatal counseling, completed a
questionnaire and were offered the option
of cfDNA by a genetic counselor.
Downstream data through 28weeks'
gestation were collected from the
electronic medical record (EMR). The EMR
was also used to identify a matched
historical cohort from 1 year prior to cfDNA
availability. Rates of invasive prenatal
procedures were compared using
McNemar's test.
Twenty-two subjects (11%) in the prospective
cohort underwent an invasive prenatal
procedure compared with 58 (29%) in the
historical cohort (p<0.0001). Safety and
accuracy were the most important factors
in considering cfDNA. At the time of survey,
only 12% of women indicated being very
comfortable with the possibility of
undergoing amniocentesis.
This prospective study demonstrates a 62%
reduction in invasive prenatal procedures
after cfDNA testing and finds safety,
accuracy, and personal beliefs key to
women's decision-making.
69
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Williams et
al 2015)
Historical
control
III-3 3,944 Aim: to understand the impact of cfDNA on
genetics counseling referrals, diagnostic
testing with CVS/amniocentesis, and
appropriate use of CFDNA TESTING.
Setting: United States
Population: women referred for genetic
counseling and prenatal testing
Methods: Data from the 2 years preceding
the introduction of cfDNA (pre-cfDNA) and
2 years following (post-cfDNA) were
analysed.
Outcomes: The primary outcome was the
difference in the number of women referred
for genetic counseling and prenatal
diagnosis during the pre-cfDNA period
compared with the post-cfDNA period. The
secondary outcome was the difference in
the number of women referred who were
not considered candidates for cfDNA
between the two study periods.
There was a statistically significant reduction
(28.4%) in the number of referrals for genetic
counseling and diagnostic testing in the
post-cfDNA compared with the pre-cfDNA
period (2,824 vs 3,944, P=0.001).
During the post-cfDNA period there was a
significant reduction in referrals of women
who would not be candidates for cfDNA
(467 pre-cfDNA vs 285 post-cfDNA, P=0.043).
In women who had diagnostic testing with
CVS during the study period, 32.4% of the
aneuploidies identified would not have
been detected by cfDNA.
The data suggest that an increasing number
of potential patients are being offered
cfDNA screening instead of diagnostic
testing, including those at risk for fetal single
gene disorders and aneuploidies not
detectable by cfDNA, potentially leading to
misdiagnosis.
70
1.8 Factors affecting uptake of cell-free fetal DNA testing by women
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Chan et al
2015)
Historical
control
III-3 1,251 Aim: to evaluate the uptake of cfDNA
screening after a high-risk screening result
for trisomy 21
Setting: Hong Kong
Population: Chinese women who had a
high-risk (term risk >1:250) first-trimester or
second-trimester screening test at three
public hospitals.
Method: Association between maternal and
pregnancy characteristics on women's test
choice was assessed after adjusting for
confounding factors
Outcomes: rate of declining further testing
and obstetric and maternal factors
impacting on patient's selection of testing
options.
Nulliparous women with a spontaneous
[adjusted odds ratio (aOR)=2.18, 95%CI 1.63-
2.92] or assisted reproduction pregnancy
(aOR=3.95, 95% CI 1.6-9.32) were more likely
to choose cfDNA. Women with an adjusted
risk of '>1:10' (aOR=7.36, 95% CI 4.22-12.8)
and '1:10 to 1:50' (aOR=1.53, 95% CI 1.01-
2.32) were more likely to opt for chorionic villi
sampling or amniocentesis.
71
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Chetty et
al 2013)
Historical
control
III-3 1,036 Aim: to investigate how the introduction of
cfDNA testing impacted women's testing
choices following a positive prenatal
screening (PNS) result.
Setting: United States
Population: Women with a positive prenatal
screening test result (first and/or trimester
serum analytes and nuchal translucency
ultrasound)
Method: Women were offered cfDNA or
invasive prenatal diagnosis.
Outcomes: Rates of invasive testing and
declining follow-up were compared with
testing decisions the prior year. Differences
were compared using t-test and chi-square.
Multivariable logistic regression was
performed to identify predictors of test
choice.
Race/ethnicity and timing of results (first
versus second trimester) were predictors of
testing choices; payer and maternal age
were not.
72
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Gil et al
2015a)
Cohort
study
III-2 6,651 Aim: to examine the factors affecting
patient decisions concerning their options.
Setting: United Kingdom
Population: Women undergoing first
trimester combined screening for fetal
trisomies 21, 18 and 13
Methods: Women with a combined-test risk
of ≥1:100 (high risk) (n=260; 3.9%) were
offered the options of chorionic villus
sampling (CVS), cfDNA testing or no further
testing and those with a risk of 1:101 to
1:2500 (intermediate risk) (n=2,017; 30.3%)
were offered cfDNA or no further testing. Risk
was low in 4,374 (65.8%).
Outcomes: Logistic regression analysis was
used to determine which factors among
maternal characteristics, fetal nuchal
translucency thickness (NT) and risk for
trisomies were significant predictors of
opting for CVS in the high-risk group and
opting for cfDNA testing in the intermediate-
risk group.
In the high-risk group, 104 (40.0%) women
opted for CVS; predictors for CVS were
increasing fetal NT and increasing risk for
trisomies, while the predictor against CVS
was being of Afro-Caribbean racial origin (r
= 0.366).
In the intermediate-risk group, 1,850 (91.7%)
women opted for cfDNA testing; predictors
for cfDNA testing were increasing maternal
age, increasing risk for trisomies and
university education, while predictors
against cfDNA testing were being of Afro-
Caribbean racial origin, smoking and being
parous (r = 0.105).
73
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Han et al
2015)
Cohort
study
III-2 5,694 Aim: To determine the influence of free
invasive prenatal testing on the uptake of
cfDNA testing.
Setting: China
Population: women at risk of fetal trisomy
Method: women were given the option of
cfDNA or invasive prenatal testing. Invasive
prenatal testing was offered free of charge
to women with a local Hukou (household
registration); however, women without a
local Hukou were charged for invasive
prenatal testing. Both women with and
without a local Hukou were charged for
cfDNA.
Outcomes: Effect of cost on uptake
During the first year, 2,647 women with a
positive trisomy 21 screening test were
referred (474 with and 2,173 without a local
Hukou). Only 1.6% of the women with a local
Hukou underwent cfDNA, while this
proportion was 20.6% in the women without
a local Hukou.
During the second year, the price of cfDNA
was reduced. The total number of women
referred was 3,047 (502 women with and
2,545 women without a local Hukou). The
uptake of cfDNA in women without a local
Hukou doubled, but the uptake of cfDNA
remained stable in women with a local
Hukou.
74
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Maiz et al
2016)
Cohort
study
III-2 1,083 Aim: first to assess the uptake of cell free
DNA (cfDNA) testing after a combined test
and the maternal and fetal factors that
influenced this decision, and second, to
assess the uptake and factors that influence
the choice of invasive testing.
Setting: Spain
Population: women with singleton
pregnancies who had a combined test for
screening for Down syndrome between
11 + 0 and 13 + 6 weeks.
Methods: maternal records were reviewed
retrospectively
Outcomes: Multivariate logistic regression
analysis was used to determine factors that
affected the uptake of cfDNA test and
invasive testing among risk for trisomies 21,
18, and 13, maternal characteristics and
fetal nuchal translucency (NT) thickness.
Two-hundred fifty-seven (23.7%) women had
a cfDNA test, 89 (8.2%) had an invasive test,
and 737 (68.1%) had no further test.
The uptake of cfDNA increased with the risk
for trisomies (p<0.001), maternal age
(p=0.013), and was higher in nulliparous
women (p=0.004).
The uptake of invasive testing increased with
the risk for trisomies (p<0.001) and NT
thickness (p<0.001).
75
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Poon et al
2015)
Historical
control
III-3 1,069 Aim: To investigate how the introduction of
cfDNA testing influenced women's testing
choices following a positive Down syndrome
screening.
Setting: Hong Kong
Population: Women (largely Chinese) with a
singleton pregnancy and a positive trisomy
21 screening (first trimester combined screen
or second trimester screening depending on
gestational age at presentation).
Methods: With the use of descriptive
statistics and a χ2 test, rates of women
choosing the invasive test and those who
declined further testing were compared
before and after the introduction of cfDNA.
We also compared demographic factors
with rates of different options including an
invasive test, cfDNA or ‘declined further
testing’. Predictors of accepting cfDNA and
an invasive test were analyzed with multiple
logistic regression. Conventional screening
was funded publicly, but cfDNA was not.
Outcomes: differences in the uptake rates of
invasive prenatal diagnosis (IPD) or no
testing before and after the introduction of
cfDNA and factors affecting choices.
In multivariable analysis, first trimester
screening, nulliparity and working women
were significant predictors of accepting
cfDNA, while only nulliparity was a predictor
of declining IPD (OR = 0.61).
76
Study ref Design LoE N Aim, setting, population, methods Results Comments
(Vahanian
et al 2014)
Cohort
study
III-2 235 Aim: To evaluate factors associated with
patient acceptance of noninvasive
prenatal testing for trisomy 21, 18 and 13 via
cfDNA.
Setting: United States
Population: Women with advanced
maternal age, personal or family history of
chromosomal anomalies, fetal ultrasound
anomaly or positive maternal serum
screening test.
Method: Patients were identified
retrospectively through our perinatal
ultrasound database
Outcomes: demographic information,
testing indication and insurance coverage
were compared between patients who
accepted the test and those who declined.
Ninety-three patients (40%) accepted
testing and 142 (60%) declined. Women who
accepted cfDNA testing were more
commonly white, had private insurance and
had more than one testing indication. There
was no statistical difference in the number
or the type of testing indications.
Multivariable logistic regression analysis was
then used to assess individual variables.
After controlling for race, patients with
public insurance were 83% less likely to
accept cfDNA testing than those with
private insurance (3% vs. 97%, adjusted RR
0.17, 95% CI 0.05-0.62).
77
1.9 Cost-effectiveness of cell-free DNA testing
Australian studies
Study ref Design LoE N Aim, setting, population, method Results Comments
(Ayres et al
2014)
Cost-
effectiveness
analysis
— 300,000 Aim: To evaluate the cost-effectiveness of
different strategies of cfDNA for trisomy 21
screening in comparison with current
practice.
Setting: Australia
Population: A theoretical cohort of singleton
pregnancies
Methods: The strategies compared were the
following: current practice, cfDNA as a
second-tier investigation, cfDNA only in
women >35 years, cfDNA only in women >40
years and cfDNA for all women. The direct
costs (low and high estimates) were derived
using both health system costs and patient
out-of-pocket expenses. The number of
trisomy 21 cases detected and procedure-
related losses (PRL) were compared
between strategies. The incremental cost
per case detected was the primary
measure of cost-effectiveness.
Universal cfDNA costs an additional
$134,636,832 compared with current
practice, but detects 123 more trisomy 21
cases (at an incremental cost of $1,094,608
per case) and avoids 90 PRL.
cfDNA for women >40 years was the most
cost-effective strategy, costing an
incremental $81,199 per additional trisomy
21 case detected and avoiding 95 PRL.
The cost of cfDNA needs to decrease
significantly if it is to replace current practice
on a purely cost-effectiveness basis.
However, it may be beneficial to use cfDNA
as first-line screening in selected high-risk
patients. Further evaluation is needed to
consider the longer-term costs and benefits
of screening.
Study assumed a
sensitivity of 98%
and specificity
of 97% for cfDNA
testing. No
failure rate
assigned.
Estimates based
on costs of
$102.95 for cFTS,
$575 for cfDNA
testing and
$528.95 for
invasive testing.
78
Study ref Design LoE N Aim, setting, population, method Results Comments
(O'Leary et
al 2013)
Cohort study — 32,478 Aim: To analyse the cost-effectiveness and
performance of cfDNA testing for high-risk
pregnancies following first-trimester
screening compared with current practice.
Setting: Western Australia
Population: singleton pregnancies screened
between January 2005 and December 2006
Methods: A decision-tree analysis was used
to compare the costs and benefits of
current practice of first-trimester screening
with a testing pathway incorporating cfDNA.
We applied the model, adding Medicare
rebate data as a measure of public health
system costs. The analyses reflect the actual
uptake of screening and diagnostic testing
and pregnancy outcomes in this cohort.
If cfDNA testing was adopted by all women
identified as high risk by cFTS, up to 7 (2 per
10,000 women) additional trisomy 21 fetuses
could be confirmed.
The introduction of second-line cfDNA
testing would reduce the number of invasive
diagnostic procedures in high-risk women by
88%.
The cost per trisomy 21 case confirmed
including cfDNA was 9.7% higher ($56,360)
than the current prenatal testing strategy
($51,372) at a total cost of $3.91 million
compared with $3.57 million over 2 years in
Western Australia.
Analysis
assumed a cost
of $AU743 for
cfDNA testing.
Other costs were
based on
Medicare
rebates (85% of
schedule fee).
Downstream
costs such as
termination and
the lifetime cost
of care of an
individual with
trisomy 21 were
not included.
79
Overseas studies
Study ref Design LoE N Aim, setting, population, method Results Comments
(Benn et al
2015)
Cost-
effectiveness
analysis
— >4m Aim: To analyze the economic value of
replacing conventional fetal aneuploidy
screening approaches with cfDNA testing in
the general pregnancy population.
Setting: United States
Population: annual US pregnancy
population
Methods: Sensitivity and specificity for fetal
aneuploidies, trisomy 21, trisomy 18, trisomy
13, and monosomy X, were estimated using
published data and modeling of both first-
and second trimester screening. Costs were
assigned for each prenatal test component
and for an affected birth. The overall cost to
the healthcare system considered screening
costs, the number of aneuploid cases
detected, invasive procedures performed,
procedure-related euploid losses, and
affected pregnancies averted. Sensitivity
analyses evaluated the effect of variation in
parameters. Costs were reported in 2014 US
Dollars.
Replacing conventional screening with
cfDNA would reduce healthcare costs if it
can be provided for $744 or less in the
general pregnancy population. The most
influential variables were timing of screening
entry, screening costs, and pregnancy
termination rates.
Of the 13,176 affected pregnancies
undergoing screening, cfDNA detected
96.5% (12,717/13,176) of cases, compared
with 85.9% (11,314/13,176) by conventional
approaches. cfDNA reduced invasive
procedures by 60.0%, with cfDNA and
conventional methods resulting in 24,596
and 61,430 invasive procedures,
respectively. The number of procedure-
related euploid fetal losses was reduced by
73.5% (194/264) in the general screening
population
80
Study ref Design LoE N Aim, setting, population, method Results Comments
(Beulen et
al 2014)
Cost-
effectiveness
analysis
— — Aim: to provide more information regarding
the consequences of implementing CFDNA
TESTING in a national programme for
prenatal screening.
Setting: The Netherlands
Methods: A decision-analytic model was
developed to compare costs and outcomes
of current clinical practice in The
Netherlands using conventional screening
only, with two alternatives: implementing
cfDNA as an optional secondary screening
test for those pregnancies complicated by a
high risk for T21, and implementing cfDNA as
primary screening test, replacing
conventional screening. Probability
estimates were derived from a systematic
review of international literature. Costs were
determined from a health-care perspective.
Data were analysed to obtain outcomes,
total costs, relative costs and incremental
cost-effectiveness ratios (ICERs) for the
different strategies. Sensitivity analysis was
used to assess the impact of assumptions on
model results.
Implementing cfDNA as an optional
secondary, or as primary screening test will
increase T21 detection rate by 36% (from
46.8% to 63.5%) and 54% (from 46.8% to
72.0%), simultaneously decreasing the
average risk of procedure-related
miscarriage by 44% (from 0.0168% to
0.0094% per pregnant woman) and 62%
(from 0.0168% to 0.0064% per pregnant
woman), respectively.
None of the strategies clearly dominated:
current clinical practice is the least costly,
whereas implementing cfDNA will cause
total costs of the programme to increase by
21% (from 257.09 to 311.74 per pregnant
woman), leading to an ICER of k94 per
detected case of T21, when utilised as an
optional secondary screening test and by
157% (from 257.09 to 660.94 per pregnant
woman), leading to an ICER of k460 per
detected case of T21, when utilised as
primary screening test. However,
implementing cfDNA as triage test did result
in the lowest expected relative costs per
case of T21 diagnosed (k141).
cfDNA should be implemented in national
health care as an optional secondary
screening test for those pregnancies
complicated by a high risk for T21.
81
Study ref Design LoE N Aim, setting, population, method Results Comments
(Cuckle et
al 2013)
Cost-
effectiveness
analysis
— Aim: to determine the principal factors
contributing to the cost of avoiding a birth
with Down syndrome by using cell-free DNA
(cfDNA) to replace conventional screening.
Setting: United States
Methods: A range of unit costs were
assigned to each item in the screening
process. Detection rates were estimated by
meta-analysis and modeling. The marginal
cost associated with the detection of
additional cases using cfDNA was estimated
from the difference in average costs divided
by the difference in detection.
The main factor was the unit cost of cfDNA
testing. For example, replacing a combined
test costing $150 with 3% false-positive rate
and invasive testing at $1000, by cfDNA tests
at $2000, $1500, $1000, and $500, the
marginal cost is $8.0, $5.8, $3.6, and $1.4m,
respectively. Costs were lower when
replacing a quadruple test and higher for a
5% false-positive rate, but the relative
importance of cfDNA unit cost was
unchanged. A contingent policy whereby
10% to 20% women were selected for cfDNA
testing by conventional screening was
considerably more cost-efficient. Costs were
sensitive to cfDNA uptake.
Potential conflict
of interest
82
Study ref Design LoE N Aim, setting, population, method Results Comments
(Evans et al
2015)
Cost-
effectiveness
analysis
— Aim: To determine whether implementation
of primary cell-free fetal DNA (cfDNA)
screening would be cost-effective in the
USA and to evaluate potential lower-cost
alternatives.
Setting: United States
Methods: Three strategies to screen for
trisomy 21 were evaluated using decision
tree analysis: 1) a primary strategy in which
cfDNA screening was offered to all patients,
2) a contingent strategy in which cfDNA
screening was offered only to patients who
were high risk on traditional first-trimester
screening and 3) a hybrid strategy in which
cfDNA screening was offered to all patients
>35years of age and only to
patients<35years who were high risk after
first-trimester screening. Four traditional
screening protocols were evaluated, each
assessing nuchal translucency (NT) and
pregnancy-associated plasma protein-A
(PAPP-A) along with either free or total beta-
human chorionic gonadotropin (beta-hCG),
with or without nasal bone (NB) assessment.
Utilizing a primary cfDNA screening strategy,
the cost per patient was 1017 US$. With a
traditional screening protocol using free
beta-hCG, PAPP-A and NT assessment as
part of a hybrid screening strategy, a
contingent strategy with a 1/300 cut-off and
a contingent strategy with a 1/1000 cut-off,
the cost per patient was 474, 430 and 409
US$, respectively. Findings were similar using
the other traditional screening protocols.
Marginal cost per viable case detected for
the primary screening strategy as compared
to the other strategies was 3-16 times
greater than the cost of care for a missed
case.
Primary cfDNA screening is not currently a
cost-effective strategy. The contingent
strategy was the lowest-cost alternative,
especially with a risk cut-off of 1/1000. The
hybrid strategy, although less costly than
primary cfDNA screening, was more costly
than the contingent strategy.
83
Study ref Design LoE N Aim, setting, population, method Results Comments
(Fairbrother
et al 2016)
Cost-
effectiveness
analysis
— Aim: To estimate the cost-effectiveness of
fetal aneuploidy screening in the general
pregnancy population using cfDNA testing
as compared to first trimester combined
screening (FTS) with serum markers and NT
ultrasound.
Setting: United States
Methods: Using a decision-analytic model,
we estimated the number of fetal T21, T18,
and T13 cases identified prenatally, the
number of invasive procedures performed,
corresponding normal fetus losses, and costs
of screening using FTS or cfDNA. Modelling
was based on a 4 million pregnant women
cohort, which represents annual births in the
United States.
For the general pregnancy population,
cfDNA testing identified 15% more trisomy
cases, reduced invasive procedures by 88%,
and reduced iatrogenic fetal loss by 94% as
compared to FTS. The cost per trisomy case
identified with FTS was 497 909. At a cfDNA
testing unit cost of 453 and below, there
were cost savings as compared to FTS.
Accounting for additional trisomy cases
identified by cfDNA testing, a cfDNA testing
unit cost of 665 provided the same per
trisomy cost as that of FTS.
Potential conflict
of interest (one
author an
industry
employee)
(Garfield &
Armstrong
2016)
Cost-
effectiveness
analysis
— 100,000 Aim: to evaluate the impact of
incorporating cfDNA testing into routine
high-risk maternal screening practice.
Setting: United States
Methods: The multi-stage transition
probability model leveraged published cost
estimates from Medicare as well as practice
patterns and disease rates from published
literature.
The model demonstrates that inclusion of
the verifi™ prenatal test provides clear
clinical benefits. These include a 66 percent
reduction in invasive diagnostic induced
miscarriages and 38% more women
receiving a T21 diagnosis. Total costs for
prenatal screening and diagnosis for fetal
aneuploidies are reduced by 1% annually.
Industry-funded
research
84
Study ref Design LoE N Aim, setting, population, method Results Comments
(Neyt et al
2014)
Cost-
effectiveness
analysis
— Aim: to estimate the consequences of
introducing cfDNA testing for the detection
of T21.
Setting: Belgium
Methods: A cost-consequences analysis was
performed presenting the impact on
benefits, harms and costs. Context-specific
real-world information was available to set
up a model reflecting the current screening
situation in Belgium. This model was used to
construct the second and first line cfDNA
screening scenarios applying information
from the literature on cfDNA test accuracy.
Introducing cfDNA in the first or second line
reduces harm by decreasing the number of
procedure-related miscarriages after
invasive testing. In contrast with cfDNA in the
second line, offering cfDNA in the first line
additionally will miss fewer cases of T21 due
to fewer false-negative test results. The
introduction of cfDNA in the second line
results in cost savings, which is not true for
cfDNA at the current price in the first line. If
cfDNA is offered to all pregnant women, the
price should be lowered to about 150 to
keep the screening cost per T21 diagnosis
constant.
85
Study ref Design LoE N Aim, setting, population, method Results Comments
(Okun et al
2014)
Cost-
effectiveness
analysis
— Aim: To examine the cost and performance
implications of introducing cell-free fetal
DNA (cfDNA) testing within modeled
scenarios in a publicly funded Canadian
provincial Down syndrome (DS) prenatal
screening program.
Setting: Canada
Method: Two clinical algorithms were
created: the first to represent the current
screening program and the second to
represent one that incorporates cfDNA
testing. From these algorithms, eight distinct
scenarios were modeled to examine: (1) the
current program (no cfDNA), (2) the current
program with first trimester screening (FTS) as
the nuchal translucency-based primary
screen (no cfDNA), (3) a program
substituting current screening with primary
cfDNA, (4) contingent cfDNA with current
FTS performance, (5) contingent cfDNA at a
fixed price to result in overall cost
neutrality,(6) contingent cfDNA with an
improved detection rate (DR) of FTS, (7)
contingent cfDNA with higher uptake of FTS,
and (8) contingent cfDNA with optimized FTS
(higher uptake and improved DR).
This modeling study demonstrates that
introducing contingent cfDNA testing
improves performance by increasing the
number of cases of trisomy 21 detected
prenatally, and reducing the number of
amniocenteses performed and
concomitant iatrogenic pregnancy loss of
pregnancies not affected by trisomy 21.
Contingent models of cfDNA testing can
improve overall screening performance
while maintaining the provision of an 11- to
13-week scan. Costs are modestly
increased, but cost per prenatally detected
case of DS is decreased
86
Study ref Design LoE N Aim, setting, population, method Results Comments
(Walker et
al 2015)
Cost-
effectiveness
analysis
— Aim: to (1) determine the optimum maternal
serum screening risk cutoff for contingent
cfDNA testing and (2) compare the cost
effectiveness of optimized contingent
cfDNA testing to universal cfDNA testing and
conventional MSS.
Setting: United States
Methods: Decision-analytic model using
micro-simulation and probabilistic sensitivity
analysis. We evaluated cost effectiveness
from three perspectives: societal,
governmental, and payer.
From a societal perspective, universal cfDNA
dominated both contingent cfDNA and
maternal serum screening. From a
government and payer perspective,
contingent cfDNA dominated maternal
serum screening. Compared to contingent
cfDNA, adopting a universal cfDNA would
cost $203,088 for each additional case
detected from a government perspective
and $263,922 for each additional case
detected from a payer perspective.
87
1.10 Guidelines and statements for research question 1
Guidelines and statements will inform revision of the narrative.
(ACOG 2015) Noninvasive prenatal screening that uses cell-free DNA from the plasma of pregnant women offers tremendous potential as a screening
method for fetal aneuploidy. A number of laboratories have validated different techniques for the use of cell-free DNA as a screening test for
fetal aneuploidy. All tests have a high sensitivity and specificity for trisomy 18 and trisomy 21, regardless of which molecular technique is used.
Women whose results are not reported, indeterminate, or uninterpretable (a "no call" test result) from cell-free DNA screening should receive
further genetic counseling and be offered comprehensive ultrasound evaluation and diagnostic testing because of an increased risk of
aneuploidy. Patients should be counseled that cell-free DNA screening does not replace the precision obtained with diagnostic tests, such as
chorionic villus sampling or amniocentesis and, therefore, is limited in its ability to identify all chromosome anomalies. Cell-free DNA screening
does not assess risk of fetal anomalies such as neural tube defects or ventral wall defects. Patients who are undergoing cell-free DNA
screening should be offered maternal serum alpha-fetoprotein screening or ultrasound evaluation for risk assessment. The cell-free DNA
screening test should not be considered in isolation from other clinical findings and test results. Management decisions, including termination
of the pregnancy, should not be based on the results of the cell-free DNA screening alone. Patients should be counseled that a negative cell-
free DNA test result does not ensure an unaffected pregnancy. Given the performance of conventional screening methods, the limitations of
cell-free DNA screening performance, and the limited data on cost-effectiveness in the low-risk obstetric population, conventional screening
methods remain the most appropriate choice for first-line screening for most women in the general obstetric population.
88
(Chitayat et al
2011)
1. All pregnant women in Canada, regardless of age, should be offered, through an informed counselling process, the option of a prenatal
screening test for the most common clinically significant fetal aneuploidies in addition to a second trimester ultrasound for dating, assessment
of fetal anatomy, and detection of multiples. (I-A) 2. Counselling must be non-directive and must respect a woman's right to accept or decline
any or all of the testing or options offered at any point in the process. (III-A) 3. Maternal age alone is a poor minimum standard for prenatal
screening for aneuploidy, and it should not be used a basis for recommending invasive testing when non-invasive prenatal screening for
aneuploidy is available. (II-2A) 4. Invasive prenatal diagnosis for cytogenetic analysis should not be performed without multiple marker
screening results except for women who are at increased risk of fetal aneuploidy (a) because of ultrasound findings, (b) because the
pregnancy was conceived by in vitro fertilization with intracytoplasmic sperm injection, or (c) because the woman or her partner has a history
of a previous child or fetus with a chromosomal anomaly or is a carrier of a chromosome rearrangement that increases the risk of having a
fetus with a chromosomal anomaly. (II-2E) 5. At minimum, any prenatal screen offered to Canadian women who present for care in the first
trimester should have a detection rate of 75% with no more than a 3% false-positive rate. The performance of the screen should be
substantiated by annual audit. (III-B) 6. The minimum standard for women presenting in the second trimester should be a screen that has a
detection rate of 75% with no more than a 5% false-positive rate. The performance of the screen should be substantiated by annual audit. (III-
B) 7. First trimester nuchal translucency should be interpreted for risk assessment only when measured by sonographers or sonologists trained
and accredited for this service and when there is ongoing quality assurance (II-2A), and it should not be offered as a screen without
biochemical markers in singleton pregnancies. (I-E) 8. Evaluation of the fetal nasal bone in the first trimester should not be incorporated as a
screen unless it is performed by sonographers or sonologists trained and accredited for this service and there is ongoing quality assurance. (II-
2E) 9. For women who undertake first trimester screening, second trimester serum alpha fetoprotein screening and/or ultrasound examination is
recommended to screen for open neural tube defects. (II-1A) 10. Timely referral and access is critical for women and should be facilitated to
ensure women are able to undergo the type of screening test they have chosen as first trimester screening. The first steps of integrated
screening (with or without nuchal translucency), contingent, or sequential screening are performed in an early and relatively narrow time
window. (II-1A) 11. Ultrasound dating should be performed if menstrual or conception dating is unreliable. For any abnormal serum screen
calculated on the basis of menstrual dating, an ultrasound should be done to confirm gestational age. (II-1A) 12. The presence or absence of
soft markers or anomalies in the 18- to 20-week ultrasound can be used to modify the a priori risk of aneuploidy established by age or prior
screening.
89
(Dondorp et al
2015)
This paper contains a joint ESHG/ASHG position document with recommendations regarding responsible innovation in prenatal screening with
cfDNA testing. By virtue of its greater accuracy and safety with respect to prenatal screening for common autosomal aneuploidies, cfDNA has
the potential of helping the practice better achieve its aim of facilitating autonomous reproductive choices, provided that balanced pretest
information and non-directive counseling are available as part of the screening offer. Depending on the health-care setting, different
scenarios for cfDNA-based screening for common autosomal aneuploidies are possible. The trade-offs involved in these scenarios should be
assessed in light of the aim of screening, the balance of benefits and burdens for pregnant women and their partners and considerations of
cost-effectiveness and justice. With improving screening technologies and decreasing costs of sequencing and analysis, it will become
possible in the near future to significantly expand the scope of prenatal screening beyond common autosomal aneuploidies. Commercial
providers have already begun expanding their tests to include sex-chromosomal anomalies and microdeletions. However, multiple false
positives may undermine the main achievement of cfDNA testing in the context of prenatal screening: the significant reduction of the invasive
testing rate. This document argues for a cautious expansion of the scope of prenatal screening to serious congenital and childhood disorders,
only following sound validation studies and a comprehensive evaluation of all relevant aspects. A further core message of this document is
that in countries where prenatal screening is offered as a public health programme, governments and public health authorities should adopt
an active role to ensure the responsible innovation of prenatal screening on the basis of ethical principles. Crucial elements are the quality of
the screening process as a whole (including non-laboratory aspects such as information and counseling), education of professionals,
systematic evaluation of all aspects of prenatal screening, development of better evaluation tools in the light of the aim of the practice,
accountability to all stakeholders including children born from screened pregnancies and persons living with the conditions targeted in
prenatal screening and promotion of equity of access.
(Gregg et al
2016)
The isolation of fetal DNA fragments from maternal circulation in sufficient quantity and sizes, together with proprietary bioinformatics tools,
now allows patients the option of noninvasive fetal aneuploidy screening. However, obstetric care providers must become famil iar with the
advantages and disadvantages of the utilization of this approach as analysis of cell-free fetal DNA moves into clinical practice. Once
informed, clinicians can provide efficient pretest and posttest counseling with the goal of avoiding patient harm. It is in the public's best
interest that test results contain key elements and that laboratories adhere to established quality control and proficiency testing standards. The
analysis of cell-free fetal DNA in maternal circulation for fetal aneuploidy screening is likely the first of major steps toward the eventual
application of whole fetal genome/whole fetal exome sequencing.
(Langlois &
Brook 2013)
Recommendations 1. Non-invasive prenatal testing using massive parallel sequencing of cell-free fetal DNA to test for trisomies 21, 18, and 13
should be an option available to women at increased risk in lieu of amniocentesis. Pretest counselling of these women should include a
discussion of the limitations of non-invasive prenatal testing. (II-2A) 2. No irrevocable obstetrical decision should be made in pregnancies with a
positive non-invasive prenatal testing result without confirmatory invasive diagnostic testing. (II-2A) 3. Although testing of cell-free fetal DNA in
maternal plasma appears very promising as a screening test for Down syndrome and other trisomies, studies in average-risk pregnancies and a
significant reduction in the cost of the technology are needed before this can replace the current maternal screening approach using
biochemical serum markers with or without fetal nuchal translucency ultrasound. (III-A).
90
(Michaelson-
Cohen et al
2014)
Prenatal testing of cell-free fetal DNA in maternal plasma is a novel approach, designed for detecting common aneuploidies in the fetus. The
Israeli Society of Medical Geneticists (ISMG) supports its use according to the guidelines stated herein. The clinical data collected thus far
indicate that cfDNA testing is highly sensitive in detecting trisomies 21 and 18, and fairly sensitive in detecting trisomy 13 and sex chromosome
aneuploidies. Because false-positive results may occur, an abnormal result must be validated by invasive prenatal testing. At this juncture,
cfDNA testing does not replace existing prenatal screening tests for Down syndrome, as these are relatively inexpensive and cost-effective.
Nonetheless, cfDNA testing may be offered to women considered to be at high risk for fetal chromosomal anomalies as early as 10 weeks of
gestation. The ISMG states that cfDNA testing should be an informed patient choice, and that pretest counseling regarding the limitations of
cfDNA testing is warranted. Women at high risk for genetic disorders not detected by cfDNA testing should be referred for genetic counseling.
A normal test result may be conveyed by a relevant healthcare provider, while an abnormal result should be discussed during a formal
genetic consultation session.
(RANZCOG
2015)
Cell-free DNA (cfDNA) screening using maternal plasma can be performed reliably from 10 weeks. This screening test became widely
available in Australia in 2013 and has the highest sensitivity and specificity of all the screening tests for Down syndrome. However, cfDNA
testing is currently more expensive than CFTS and must be self-funded (currently no Medicare or private insurance rebate). This direct cost
currently poses a significant barrier to accessibility and widespread clinical implementation.
Consensus-based recommendation:
• Accurate dating, confirmation of viability and determination of the number of embryos by ultrasound is recommended prior to cfDNA
testing.
• cfDNA based screening for fetal aneuploidy is not diagnostic. The chance of having an affected fetus following an abnormal/high risk
cfDNA result (ie the positive predictive value, PPV) may be < 50%, depending on the specific chromosome involved and the background
risk of the woman. Confirmatory diagnostic testing is strongly recommended after an abnormal cfDNA result.
• If a woman has received a normal/low risk result from a cfDNA testing test, an additional risk calculation for aneuploidy (e.g. by combined
first trimester or second trimester serum screening) is not recommended as this will increase the false positive rate without substantially
improving the detection rate.
• The presence of a fetal structural anomaly remains an important indication for invasive prenatal testing, even in the presence of a prior
normal/low risk cfDNA result.
• Pre-test counselling should include informed decision making regarding testing for fetal sex and sex chromosome aneuploidy. Women
should be given the choice to opt out of receiving this information.
(SMFM 2015b) Recent advances in technology have created exciting opportunities to expand and improve genetic testing options that are available to
women during pregnancy. However, the novelty and complexity of these technologies, combined with the commercial interest to implement
these tests rapidly into routine clinical care, have created challenges for physicians and patients and potentially will lead to misunderstanding,
misuse, and unintended consequences. The purpose of this document was to aid clinicians in their day-to-day practice of counseling patients
regarding prenatal aneuploidy testing options with cell-free DNA screening, which includes how it compares to current testing methods,
potential benefits and harms, and its limitations and caveats.
91
(SMFM 2015a) The purpose of this statement is to clarify that the Society for Maternal-Fetal Medicine (SMFM) does not recommend that cell-free DNA
aneuploidy screening be offered to all pregnant women, nor does it suggest a requirement for insurance coverage for cell-free DNA screening
in women at low risk of aneuploidy. However, SMFM believes, due to the ethics of patient autonomy, that the option should be available to
women who request additional testing beyond what is currently recommended by professional societies.
(Wilson et al
2013)
The BUN and FASTER studies, two prospective multicenter trials in the United States, validated the accuracy and detection rates of first and
second trimester screening previously reported abroad. These studies, coupled with the 2007 release of the American College of Obstetricians
and Gynecologists (ACOG) Practice Bulletin that endorsed first trimester screening as an alternative to traditional second trimester multiple
marker screening, led to an explosion of screening options available to pregnant women. ACOG also recommended that invasive diagnostic
testing for chromosome aneuploidy be made available to all women regardless of maternal age. More recently, another option known as
cfDNA testing became available to screen for chromosome aneuploidy. While screening and testing options may be limited due to a variety
of factors, healthcare providers need to be aware of the options in their area in order to provide their patients with accurate and reliable
information. If not presented clearly, patients may feel overwhelmed at the number of choices available. The following guideline includes
recommendations for healthcare providers regarding which screening or diagnostic test should be offered based on availability, insurance
coverage, and timing of a patient's entry into prenatal care, as well as a triage assessment so that a general process can be adapted to
unique situations.
1.11 Excluded studies for research question 1
Background papers
Background papers will inform revision of the narrative.
Health professional views
(Alexander et al
2015)
Genetic counsellors reported initially feeling cautious about offering the test, although they saw it as a positive advance for their patients at
genetic risk. Emphasis was placed on accuracy, adequate counselling provision and gatekeeping with concerns expressed about
broadening its use in the routine antenatal setting. Findings indicate the genetics model for offering prenatal testing to high risk patients can
incorporate cfDNA testing and the profession may have a role in informing its implementation in wider healthcare settings. In a wider context
this study highlights the challenges new technologies bring to genetic counsellors' practice and service structure.
(Benn et al 2014) In this study, 79.1% of participating Fellows of the American College of Obstetricians and Gynecologists supported the use of cfDNA testing as
a screen for Down syndrome for all women with 47.9% viewing cfDNA testing as a complete substitution for invasive testing. Most supported
expansion to other aneuploidies (97.5%) and severe early-onset Mendelian disorders (90.4%) but not for adult-onset disorders (29.8%) or
nonmedical sex identification (15.7%). A majority (73.2%) believed that cfDNA testing would increase pregnancy terminations for mild disease
states. Respondents favoured a role for professional societies in providing regulatory oversight.
92
(Buchanan et al
2014)
Respondents (genetic counsellors) indicated that a discussion about cfDNA testing with a patient should highlight that it is a screening test, the
detection rate is superior to that of maternal serum screening, it screens for specific conditions, and a positive cfDNA result should be
confirmed with a diagnostic test.
(Haymon et al
2014)
Assessment indicates cfDNA testing is being adopted by maternal fetal medicine specialists, largely in accord with recently published
American College of Obstetricians and Gynecologists and the Society for MFM guidelines. Cost and test performance remain factors for not
adopting cfDNA testing. Further research on clinical management based on cfDNA results and patient understanding of cfDNA results is
suggested.
(Horsting et al
2014)
Results indicate that genetic counselors value cfDNA testing as a screening option but are concerned regarding how some obstetricians and
patients make use of this testing.
(Hui et al 2015a) In a survey of members of the Australian Association of Obstetrical and Gynaecological Ultrasonologists (AAOGU) during the first year of local
availability of cell-free DNA-based prenatal testing for aneuploidy, we received 54 responses to the survey (39% response rate). Two thirds of
respondents were subspecialists in obstetric and gynaecological ultrasound or maternal fetal medicine. The majority of respondents had
already used cfDNA testing in their practice (94%). There was no significant difference in the proportion of respondents offering cfDNA to high-
risk women in private versus public practice (95 versus 82%, P = 0.14). However, inequity of access due to cost was the most common ethical
issue encountered. The vast majority continued to offer an 11–13 week ultrasound in addition to cfDNA. Almost all respondents (96%) were also
willing to offer cfDNA testing to low-risk women in December 2013 after appropriate genetic counselling.
(Hui et al 2015b) In a period of declining invasive prenatal testing, many Australian specialists are performing <25 procedures annually. Consideration of the
potential risks of bloodborne viruses is limited. Chromosomal microassays are rapidly being incorporated into clinical practice. These data
have implications for patient consent and safety, and workforce training and practice.
(Mayes et al
2016)
Overall, 85 obstetricians were surveyed. While all respondents indicated awareness of cfDNA in its traditional form, 75% (64/85) were aware of
the expanded testing option, and 14% (12/85) reported having ordered the expanded cfDNA option. A total of 91% (77/85) expressed that
practitioners need more information regarding the screening. Based on these findings and the fluid landscape of prenatal screening,
education, and reeducation of health care professionals is imperative to ensure responsible patient counseling, informed consent, and
appropriate posttest management.
(Musci et al
2013)
Of the 101 obstetricians (in the United States) that completed the survey (27% academic-based, 73% private practice), 97% offer screening to
high-risk patients and 91% offer screening to average-risk patients. With regard to current screening tests, the top three advantages were as
follows: recommendation by professional societies, no risk to the pregnancy, and long history/experience with the test, whereas the top three
limitations were as follows: patient anxiety, risks of follow-up invasive testing, and high false positives. cfDNA testing had been used by 32% of
respondents and 22% were familiar with cfDNA and the associated clinical data. The majority of physicians predicted that they would offer
cfDNA testing to high-risk women (86.1%) and average-risk women (76.2%) within 12months.
93
(Suskin et al
2016)
Results indicate substantial variation in practice regarding which patients are offered NIPS and how counselors have incorporated this
technology into existing screening routines. The majority of participants report offering NIPS in conjunction with another method of screening
for fetal aneuploidy, indicating that cfDNA testing is being used as an addition rather than as a replacement. These screening methods
primarily include nuchal translucency (NT) (45.1 %, n = 78) and first trimester serum screening, with or without an NT (19.7 %, n = 34). Furthermore,
the majority report that they would be concerned about losing the clinical value of an NT in a complete transition to cfDNA testing (85.4 %, n =
164). Counselors are evenly split on the merits of expanding the use of cfDNA testing to the general population (con: 55.3 %, n = 105; pro: 44.7
%, n = 85). The lack of consensus suggests that updated practice guidelines might benefit counselors. In addition, respondents emphasized the
need to better educate patients and providers about the risks, benefits, and limitations of the test.
(Swaney et al
2016)
Among maternal-fetal medicine fellows surveyed, >75 % reporting they are comfortable ordering cfDNA testing. Most (82 %) preferred that a
patient discuss options with a provider or genetic counselor. Three common methods used to learn about cfDNA testing were: formal
educational activities (n = 78, 69 %), self-review of the literature (n = 76, 67 %), and discussions with peers (n = 73, 65 %). On questions related to
trisomy 21, accuracy was >70 %. However, accuracy was lower regarding use in twin pregnancies (42 %) and monosomy X screening (50 %).
(Tamminga et al
2015)
Health professionals (in the Netherlands) favor offering cfDNA testing to all women; most want to maintain nuchal fold measurement. The
majority (92%) of health professionals thought cfDNA testing should include disorders characterized by neonatal death or death within the first
year of life; 52% favored testing for fetomaternal risk factors. Most health professionals thought that a broader range of disorders should be
offered as a 'fixed list of disorders' in contrast to pregnant women who mostly preferred to have a free choice.
(Yared et al
2016)
Obese women had a failure rate of 24.3% compared with 3.8% in nonobese women (P < .01). Gestational age was not associated with failure
rate (mean ± standard deviation, 13 ± 3 weeks for both screen failure and nonfailure; P = .76). The addition of a paternal cheek swab reduced
the failure rate from 10.2% in women with no swab to 3.8% in women with a swab (P < .01). In multivariable analysis, obesity and lack of a
paternal cheek swab were independent predictors of screen failure (odds ratio, 9.75; 95% confidence interval, 4.85-19.61; P < .01; and odds
ratio, 3.61; 95% confidence interval, 1.56-8.33; P < .01, respectively).
Women’s views
(Chan et al 2014) The majority of women can accept NIDT as an alternative to IPD provided that the test is 95% accurate in the diagnosis of Down syndrome.
Current evidence indicates that the detection rate of NIDT will be higher than this level.
(Farrell et al
2014b)
Women identified accuracy, early timing, testing ease, and determination of fetal sex as advantages of cfDNA testing over other screens, and
the noninvasive method of cfDNA testing as an advantage over diagnostic tests. False positive and false negative results, anxiety, cost and
insurance coverage were seen as disadvantages of cfDNA testing. Women who do not want fetal aneuploidy information most likely will not
undergo cfDNA testing, despite its advantages over other screening tests. However, given its advantages, the decision to have cfDNA testing
is straightforward for women who want genetic information about the fetus. Women emphasized the need to make autonomous, private, and
informed choices about cfDNA testing, as they would with any prenatal genetic testing option.
94
(Kellogg et al
2014)
Results suggest although mothers of children with Down syndrome believe new noninvasive testing will lead to an increase in termination of
pregnancies with Down syndrome, they do not think it is the MOST important factor. They also highlight the need to provide a diagnosis of
Down syndrome in a balanced and objective manner.
(Kooij et al 2009) Among women visiting for routine fetal anomaly ultrasound scan at 20 weeks' gestation and female medical master students, both groups
considered cfDNA testing an important asset in the reliable diagnosis of fetal aneuploidy and gender-determined genetic disorders, with the
exception of disorders manifesting themselves later in life. There was a negative response to its application for family balancing. 82% of the
pregnant women and 79% of the medical students responded positively to the question whether they consider cfDNA testing an important
asset in prenatal care. The statement that it is an asset because it enables pregnant women to bear an 'optimal child' was strongly rejected by
both groups.
(Lau et al 2012a) Over 95% of women (n=567) had complete or almost complete resolution of anxiety. Except for one, all were satisfied with the NIFTY test, and
all indicated that they would recommend the test to their friends. Conclusion: The NIFTY test was a highly specific test. Unnecessary invasive
tests and associated fetal losses could be avoided in almost all women who have a normal fetus.
(Lewis et al 2014) Respondents (women and partners in England) were overwhelmingly positive towards the introduction of cfDNA testing. Uptake is likely to be
high, and includes women who currently decline screening as well as those who will use the test for information only. Pre-test counselling to
ensure that women understand the implications of the test result is essential.
(Lewis et al
2016a)
Women were overwhelmingly positive about the opportunity to have a test that was procedurally safe, accurate, reduced the need for
invasive testing and identified cases of Down syndrome that might otherwise have been missed. Reassurance was identified as the main
motivator for accepting cfDNA testing, particularly amongst medium risk women, with high risk women inclined to accept cfDNA testing to
inform decisions around invasive testing. The current turnaround time for test result was identified as a key limitation. All the women interviewed
thought cfDNA testing should be adopted as part of NHS clinical practice, with the majority favouring cfDNA testing offered as a firstline test.
Our study highlights the potential that cfDNA testing has to positively impact women's experience of prenatal testing for aneuploidy.
(Sayres et al
2014)
Willingness to consider abortion of an affected pregnancy was the strongest correlate to interest in both cfDNA and first-trimester combined
screening, although markedly more respondents expressed an interest in some form of screening (69% and 71%, respectively) than would
consider termination. Greater educational attainment, higher income, and insurance coverage predicted interest in cfDNA screening;
stronger religious identification also corresponded to decreased interest. Prior experience with disability and genetic testing was associated
with increased interest in cfDNA screening. Several of these factors, in addition to advanced age and Asian race, were, in turn, predictive of
respondents' increased willingness to consider post-diagnosis termination of pregnancy.
(Steinbach et al
2016)
Regardless of opinion toward disability, the majority of respondents supported both the availability of screening and the decision to continue a
pregnancy positive for aneuploidy. Individuals rationalized their support with various conceptions of disability; complications of the expressivist
argument and other concerns from the disability literature were manifested in many responses analyzed.
95
(van Schendel et
al 2015)
Of the women (in the Netherlands), 51% expressed interest in having cfDNA testing, including 33% of women who had declined first-trimester
screening. The majority (73%) thought that the uptake of screening would increase with cfDNA testing. Most women agreed that testing for
life-threatening (89%), severe physical (79%), or severe mental (76%) disorders should be offered. A minority (29%) felt that prenatal screening
should also be offered for late-onset disorders. Most (41%) preferred to have a free choice from a list of disorders, 31% preferred a 'closed offer',
and 26% preferred choosing between packages of disorders. Although most women (76%) thought that screening for a broad range of
conditions would avoid much suffering, 39% feared that it would confront couples with choices, the implications of which would be difficult to
grasp.
(Verweij et al
2013b)
The pregnant women in our study (in the Netherlands) had a positive attitude regarding cfDNA testing for T21, and more than half of the
women who rejected prenatal screening would receive cfDNA testing if available. Due to the elimination of iatrogenic miscarriage, caregivers
should be aware that informed decision-making can change with respect to prenatal screening with the introduction of cfDNA testing.
(Yi et al 2013) cfDNA testing was regarded positively by women (in Hong Kong) who chose this method of screening over the routine, less expensive testing
options. Given its perceived utility, health providers need to consider whether cfDNA testing should be offered as part of universal routine care
to women at high-risk for fetal aneuploidy. If this is the case, then further development of guidelines and quality assurance will be needed to
provide a service suited to patients' needs.
Informed decision-making
(Agatisa et al
2015)
Participants voiced their desire to be informed of all conditions assessed by cfDNA testing prior to testing. They considered clinicians to be the
key provider of such information, although stated that patients have a responsibility to be knowledgeable prior to testing in order to support
informed decision-making. The use of cfDNA testing to identify sex chromosome aneuploidies and microdeletion syndromes will introduce new
challenges for clinicians to ensure pregnant women have the information and resources to make informed choices about cfDNA testing when
used for these conditions.
(Allyse et al 2014) There appears to be support for uptake of non-invasive prenatal tests. Clinical guidelines should therefore go forward in providing guidance on
how to integrate non-invasive methods into the current standard of care. However, our findings indicate that even when accuracy, which is
rated by patients as the most important aspect of prenatal testing, is significantly improved over existing screening methods and testing is
offered non-invasively, the number of individuals who reported that they would decline any testing remained the same. Attention should
therefore be directed at ensuring that the right of informed refusal of prenatal testing is not impacted by new, non-invasive methods.
(Farrell et al
2014a)
This study demonstrates that cfDNA testing will introduce new challenges for pregnant women and their health care practitioners who will be
charged with supporting informed decision-making about its use. It is critical that obstetric professionals are prepared to facilitate a patient-
centered decision-making process as its clinical application rapidly changes.
96
(Godino et al
2016)
The majority of women perceived as clear and helpful the information received at counselling, and only 12.7% had doubts left that, however,
often concerned non-pertinent issues. The impact of counselling on risk perception and decisions was limited: a minority stated their perceived
risk of foetal anomalies had either increased (6.8%) or reduced (3.6%), and only one eventually declined invasive test. The 52.6% of women
expressed a preference toward individual counselling, which also had a stronger impact on perceived risk reduction (P=0.003). Nevertheless,
group counselling had a more favourable impact on both clarity of understanding and helpfulness (P=0.0497 and P=0.035, respectively). The
idea that AMA represents an absolute indication for invasive tests appears deeply rooted; promotion of non-invasive techniques may require
extensive educational efforts targeted to both the general population and health professionals.
(Kou et al 2015) It is feasible to use a questionnaire based on the International Society for Prenatal Diagnosis 2011 statement on cfDNA testing to assess
women's knowledge of the test. The Chinese women who underwent cfDNA testing recognised the limitations, but did not understand the
complicated aspects. More information should be provided by health care professionals in order to facilitate an informed choice by patients.
More women preferred cfDNA testing as a contingent test than as a primary screening probably because of its high cost.
(Lau et al 2012b) Besides screening Down syndrome by NIFTY, most pregnant women would also like to be informed if there was suspicion of SCA. Those
screened positive should be counseled by those with experience in genetics to avoid unnecessary pregnancy termination.
(Lau et al 2016) A qualitative study was carried out using semi-structured interviews with 36 women who had undertaken cfDNA testing in Hong Kong. The
findings show that most Hong Kong Chinese women valued aspects of both relational and individual autonomy in decision-making for cfDNA
testing. Women expected support from doctors as experts on the topic and wanted to involve their husband in decision-making while
retaining control over the outcome. Somewhat surprisingly, the findings do not provide support for the involvement of family members in
decision-making for cfDNA testing. The adequacy of current interpretations of autonomy in prenatal testing policies as an individual approach
needs discussion, where policy developers need to find a balance between individual and relational approaches.
(Lewis et al 2013) The successful introduction of cfDNA testing into routine prenatal care will require guidelines and counselling strategies which ensure women
are offered this test in a way which safeguards informed consent.
(Lewis et al 2015) Health professionals should be aware that women may have incomplete information or misunderstandings about cfDNA testing. Pre-test
counselling to ensure informed decision-making is therefore important.
(Lewis et al
2016b)
Results indicate the vast majority of women (89%) made an informed choice; 95% were judged to have good knowledge, 88% had a positive
attitude and 92% had deliberated. Of the 11% judged to have made an uninformed choice, 55% had not deliberated, 41% had insufficient
knowledge, and 19% had a negative attitude. Ethnicity (OR=2.78, P=0.003) and accepting cfDNA testing (OR=16.05, P=0.021) were found to
be significant predictors of informed choice. The high rate of informed choice is likely to reflect the importance placed on the provision of pre-
test counselling in this study. It will be vital to ensure that this is maintained once cfDNA testing is offered in routine clinical practice.
(Piechan et al
2016)
Participants scored lowest on knowledge questions involving whether a negative cfDNA test result ensures a healthy baby or eliminates the
possibility of Down syndrome. Most perceived themselves to have a good basic understanding of cfDNA testing and two-thirds of the written
feedback proposed no changes to cfDNA testing administration. Overall, most patients appear satisfied with their understanding of cfDNA
testing and the testing process, yet they may not fully appreciate the limitations of this screening method.
97
(Silcock et al
2015)
Health professionals and pregnant women view the consenting process differently across antenatal test types. These differences suggest that
informed choice may be undermined with the introduction of cfDNA testing for DS into clinical practice. To maintain high standards of care,
effective professional training programmes and practice guidelines are needed which prioritize informed consent and take into account the
views and needs of service users.
(van den Heuvel
et al 2010)
This study provides the first empirical evidence to demonstrate that practitioners may view the consent process for cfDNA testing differently to
invasive testing. There is potential for the introduction of cfDNA testing to undermine women making informed choices in the context of
prenatal diagnostic testing for conditions like DS.
(van Schendel et
al 2014)
Participants (in the Netherland) felt that current prenatal screening has great disadvantages such as uncertain results and risk of miscarriage
from follow-up diagnostics. Characteristics of cfDNA testing (accurate, safe and early testing) could therefore diminish these disadvantages of
prenatal screening and help lower the barrier for participation. This suggests that cfDNA testing might allow couples to decide about prenatal
testing based mostly on their will to test or not, rather than largely based on fear of miscarriage risk or the uncertainty of results. The lower
barrier for participation was also seen as a downside that could lead to uncritical use or pressure to test. Widening the scope of prenatal
testing was seen as beneficial for severe disorders, although it was perceived difficult to determine where to draw the line. Participants argued
that there should be a limit to the scope of cfDNA testing, avoiding testing for minor anomalies. The findings suggest that cfDNA testing could
enable more meaningful decision-making for prenatal screening. However, to ensure voluntary participation, especially when testing for
multiple disorders, safeguards on the basis of informed decision-making will be of utmost importance.
Public attitudes
(Kelly &
Farrimond 2012)
In a survey of public attitudes, the majority (63%) of respondents described their first response as positive. However, respondents displayed
ambivalence, expressing positive views of individual/medical rationale for cfDNA testing and unease concerning public health rationale and
societal implications. Unease related to eugenic reasoning underlying existing prenatal testing, 'too much control' in reproduction, commercial
provision, information and support requirements for expanded testing, and limiting the use of testing.
(Lewis et al 2015) Positive reporting of cfDNA testing in the UK news media reflects the publics' broadly optimistic view towards genomic technology and
prenatal testing.
Implementation
(Hill et al 2012) Policies for implementing noninvasive prenatal diagnosis must consider the differences between womens and health professionals preferences
to ensure the needs of all stakeholders are met. Women’s strong preference for tests with no risk of miscarriage demonstrates that
consideration for safety of the fetus is paramount in decision-making. Effective pretest counseling is therefore essential to ensure women
understand the possible implications of results.
98
(Hill et al 2016) Differences in preferences were seen between women and health professionals within and between countries. Overall, women placed
greater emphasis on test safety and comprehensive information than health professionals, who emphasised accuracy and early testing.
Differences between women’s and health professionals’ preferences are marked between countries. Varied approaches to implementation
and service delivery are therefore needed and individual countries should develop guidelines appropriate for their own social and screening
contexts.
(Mackie 2016) Emerging evidence from the NIHR-funded RAPID study suggests that uptake will be high, both to help reassure more women that the baby
does not have Downs syndrome but also for women to prepare for the birth of a child with Down syndrome rather than to terminate an
affected pregnancy. There remain many questions, some of which will only be addressed when the test is used in a screening programme and
we can see what choices parents actually make and what information they need. One thing is clear though, we must distinguish this highly
accurate screening test for aneuploidy, which requires confirmation by invasive testing, from diagnostic testing, which does not require such
confirmation, in pregnancies at risk of monogenic disorders and RHD complications.
(Verweij et al
2013a)
The results suggest that implementing cfDNA testing (in the Netherlands) may be associated with an increased uptake of prenatal testing,
whereas the percentage of women who opt to terminate a pregnancy affected by trisomy 21 (T21) may likely decrease. cfDNA testing may
not lead to a vast reduction in live births of children with T21, but unlike the current situation, most will be born in families who accepted, with or
without testing, the chance of having and caring for a child with T21.
Information on the internet
(Mercer et al
2014)
Basic information about cfDNA testing use as a screening test was accurately described. Overall, sampled websites lacked balance and
comprehensive information about cfDNA testing and the complexity of decision-making involved in electing for its use. All websites were
written at reading levels higher than currently recommended levels for public health information.
(Skirton et al
2015)
The development of non-invasive prenatal testing has increased accessibility of fetal testing. Companies are now advertising prenatal testing
for aneuploidy via the Internet. While a number of websites provided balanced, accurate information, in the majority supporting evidence
was not provided to underpin the information and there was inadequate information on the need for an invasive test to definitely diagnose
aneuploidy.
Systematic reviews excluded due to low quality or overlap with high-quality systematic reviews
Study Reason for exclusion
Davis C, Cuckle H, Yaron Y (2014) Screening for Down syndrome--incidental diagnosis of
other aneuploidies. Prenat Diagn 34(11): 1044-8.
Of ten included studies, only two are specific to first trimester
screening.
Badeau, M., C. Lindsay, et al. (2015) Genomics-based non-invasive prenatal testing for
detection of fetal chromosomal aneuploidy in pregnant women. DOI:
10.1002/14651858.CD011767
Protocol
99
Study Reason for exclusion
Gil, M. M., R. Akolekar, et al. (2014). "Analysis of cell-free DNA in maternal blood in screening
for aneuploidies: Meta-analysis." Fetal Diagnosis and Therapy 35(3): 156-173.
Updated in Gil et al 2015
Hayes and Inc (2013) Noninvasive Prenatal Testing (NIPT) for fetal aneuploidy. Does not meet criteria for grading (abstract only)
Kagan, K. O., M. Hoopmann, et al. (2016). "Discordance between ultrasound and cell free
DNA screening for monosomy X." Archives of Gynecology and Obstetrics: 1-6.
Includes seven studies all of which are included in high quality
SLRs included in this review
Mersy, E., L. J. M. Smits, et al. (2013). "Noninvasive detection of fetal trisomy 21: Systematic
review and report of outcome and quality." Prenatal Diagnosis 33: 73-74. ABSTRACT
Does not meet criteria for grading (abstract only)
Mersy, E., L. J. M. Smits, et al. (2013). "Noninvasive detection of fetal trisomy 21: Systematic
review and report of quality and outcomes of diagnostic accuracy studies performed
between 1997 and 2012." Human Reproduction Update 19(4): 318-329.
Included 16 studies of which 10 were included in high quality
SLRs. Of the included studies, 9 were considered too small to
give precise results and were not included in the discussion.
Verweij, E. J., J. M. van den Oever, et al. (2012). "Diagnostic accuracy of noninvasive
detection of fetal trisomy 21 in maternal blood: a systematic review." Fetal Diagnosis &
Therapy 31(2): 81-86.
Includes two studies, both of which are included in Gil et al 2015
and Taylor Philips et al 2016
Walsh, J. M. and J. D. Goldberg (2013). "Fetal aneuploidy detection by maternal plasma
DNA sequencing: a technology assessment." Prenatal Diagnosis 33(6): 514-520.
Identified eight studies, all of which are included in high quality
SLRs
Yang, H., H. B. Xu, et al. (2015). "Systematic review of noninvasive prenatal diagnosis for
abnormal chromosome genetic diseases using free fetal DNA in maternal plasma."
Genetics and Molecular Research 14(3): 10603-10608.
Includes four studies of which three are included in high quality
SLRs and one is an early report and a later report of the paper is
included in Gil et al 2015
Studies included in high-quality systematic reviews included in this review
Study Review
Alberti, A., L. J. Salomon, et al. (2015). "Non-invasive prenatal testing for trisomy 21 based on analysis of cell-free fetal DNA
circulating in the maternal plasma." Prenatal Diagnosis 35(5): 471-476.
Mackie et al 2016
Taylor-Philips et al 2016
Ashoor, G., A. Syngelaki, et al. (2012). "Chromosome-selective sequencing of maternal plasma cell-free DNA for first-
trimester detection of trisomy 21 and trisomy 18." American Journal of Obstetrics & Gynecology 206(4): 322.e321-325.
Gil et al 2015
Taylor-Philips et al 2016
Ashoor, G., A. Syngelaki, et al. (2013). "Trisomy 13 detection in the first trimester of pregnancy using a chromosome-
selective cell-free DNA analysis method." Ultrasound in Obstetrics & Gynecology 41(1): 21-25.
Gil et al 2015
100
Study Review
Beamon, C. J., E. E. Hardisty, et al. (2014). "A single center's experience with noninvasive prenatal testing." Genetics in
Medicine 16(9): 681-687.
Taylor-Philips et al 2016
Bevilacqua, E., M. M. Gil, et al. (2015). "Performance of screening for aneuploidies by cell-free DNA analysis of maternal
blood in twin pregnancies." Ultrasound in Obstetrics & Gynecology 45(1): 61-66.
Taylor-Philips et al 2016
Bianchi, D. W., R. Lamar Parker, et al. (2014). "DNA sequencing versus standard prenatal aneuploidy screening." New
England Journal of Medicine 370(9): 799-808.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Bianchi, D. W., L. D. Platt, et al. (2012). "Genome-wide fetal aneuploidy detection by maternal plasma DNA sequencing."
Obstet Gynecol 119(5): 890-901.
Gil et al 2015
Taylor-Philips et al 2016
Bijok, J., K. Gorzelnik, et al. (2014). "[Non-invasive prenatal diagnosis of the most common aneuploidies with cell-free fetal
DNA in maternal serum--preliminary results]." Ginekologia Polska 85(3): 208-213.
Mackie et al 2016
Canick, J. A., E. M. Kloza, et al. (2012). "DNA sequencing of maternal plasma to identify Down syndrome and other
trisomies in multiple gestations." Prenatal Diagnosis 32(8): 730-734.
Gil et al 2015
Chen, E. Z., R. W. Chiu, et al. (2011). "Noninvasive prenatal diagnosis of fetal trisomy 18 and trisomy 13 by maternal plasma
DNA sequencing." PLoS ONE [Electronic Resource] 6(7): e21791.
Gil et al 2015
Taylor-Philips et al 2016
Chiu, R. W. K., R. Akolekar, et al. (2011). "Non-invasive prenatal assessment of trisomy 21 by multiplexed maternal plasma
DNA sequencing: Large scale validity study." BMJ 342(7790): 217.
Gil et al 2015
Taylor-Philips et al 2016
Comas, C., M. Echevarria, et al. (2015). "Initial experience with non-invasive prenatal testing of cell-free DNA for major
chromosomal anomalies in a clinical setting." Journal of Maternal-Fetal and Neonatal Medicine 28(10): 1196-1201.
Gil et al 2015
Taylor-Philips et al 2016
Dan, S., W. Wang, et al. (2012). "Clinical application of massively parallel sequencing-based prenatal noninvasive fetal
trisomy test for trisomies 21 and 18 in 11,105 pregnancies with mixed risk factors." Prenatal Diagnosis 32(13): 1225-1232.
Taylor-Philips et al 2016
Del Mar Gil, M., M. S. Quezada, et al. (2014). "Cell-free DNA analysis for trisomy risk assessment in first-trimester twin
pregnancies." Fetal Diagnosis and Therapy 35(3): 204-211.
Gil et al 2015
Taylor-Philips et al 2016
Ehrich, M., C. Deciu, et al. (2011). "Noninvasive detection of fetal trisomy 21 by sequencing of DNA in maternal blood: a
study in a clinical setting." American Journal of Obstetrics & Gynecology 204(3): 205.e201-211.
Gil et al 2015
Taylor-Philips et al 2016
101
Study Review
Fan, H. C., Y. J. Blumenfeld, et al. (2008). "Noninvasive diagnosis of fetal aneuploidy by shotgun sequencing DNA from
maternal blood." Proc Natl Acad Sci U S A 105(42): 16266-16271.
Mackie et al 2016
Ferres, M. A., L. Lichten, et al. (2013). "Early experience with noninvasive DNA testing for aneuploidy in prenatal care."
Prenatal Diagnosis 33: 73.
Mackie et al 2016
Ghanta, S., M. E. Mitchell, et al. (2010). "Non-invasive prenatal detection of trisomy 21 using tandem single nucleotide
polymorphisms." PLoS One 5(10): e13184.
Mackie et al 2016
Gorduza, E. V., R. Popescu, et al. (2013). "Prenatal diagnosis of 21 trisomy by quantification of methylated fetal DNA in
maternal blood: Study on 10 pregnancies." Romanian Review of Laboratory Medicine 21(3): 275-284.
Mackie et al 2016
Grömminger, S., E. Yagmur, et al. (2014). "Fetal aneuploidy detection by cell-free DNA sequencing for multiple pregnancies
and quality issues with vanishing twins." Journal of Clinical Medicine 3(3): 679-692.
Gil et al 2015
Guex, N., C. Iseli, et al. (2013). "A robust second-generation genome-wide test for fetal aneuploidy based on shotgun
sequencing cell-free DNA in maternal blood." Prenatal Diagnosis 33(7): 707-710.
Gil et al 2015
Hall, M. P., M. Hill, et al. (2014). "Non-invasive prenatal detection of trisomy 13 using a single nucleotide polymorphism- And
informatics-based approach." PLoS ONE 9(5).
Gil et al 2015
Taylor-Philips et al 2016
Hofmann, W., M. Entezami, et al. (2013). "Diagnostic accuracy for the noninvasive prenatal detection of common
autosomal aneuploidies." Prenatal Diagnosis 33: 75.
Mackie et al 2016
Hooks, J., A. J. Wolfberg, et al. (2014). "Non-invasive risk assessment of fetal sex chromosome aneuploidy through directed
analysis and incorporation of fetal fraction." Prenatal Diagnosis 34(5): 496-499.
Gil et al 2015
Huang, X., J. Zheng, et al. (2014). "Noninvasive prenatal testing of trisomies 21 and 18 by massively parallel sequencing of
maternal plasma DNA in twin pregnancies." Prenatal Diagnosis 34(4): 335-340.
Gil et al 2015
Taylor-Philips et al 2016
Jeon, Y. J., Y. Zhou, et al. (2014). "The feasibility study of non-invasive fetal trisomy 18 and 21 detection with semiconductor
sequencing platform." PLoS ONE [Electronic Resource] 9(10): e110240.
Taylor-Philips et al 2016
Jiang, F., J. Ren, et al. (2012). "Noninvasive Fetal Trisomy (NIFTY) test: an advanced noninvasive prenatal diagnosis
methodology for fetal autosomal and sex chromosomal aneuploidies." BMC Medical Genomics [Electronic Resource] 5:
57.
Gil et al 2015
Taylor-Philips et al 2016
Korostelev, S., G. Totchiev, et al. (2014). "Association of non-invasive prenatal testing and chromosomal microarray analysis
for prenatal diagnostics." Gynecological Endocrinology 30: 13-16.
Taylor-Philips et al 2016
102
Study Review
Lau, T. K., F. Chen, et al. (2012). "Noninvasive prenatal diagnosis of common fetal chromosomal aneuploidies by maternal
plasma DNA sequencing." Journal of Maternal-Fetal & Neonatal Medicine 25(8): 1370-1374.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Lau, T. K., F. Jiang, et al. (2013). "Non-invasive prenatal screening of fetal Down syndrome by maternal plasma DNA
sequencing in twin pregnancies." Journal of Maternal-Fetal and Neonatal Medicine 26(4): 434-437.
Gil et al 2015
Li, P. Q., J. Zhang, et al. (2014). "Development of noninvasive prenatal diagnosis of trisomy 21 by RT-MLPA with a new set of
SNP markers." Arch Gynecol Obstet 289(1): 67-73.
Mackie et al 2016
Liang, D., W. Lv, et al. (2013). "Non-invasive prenatal testing of fetal whole chromosome aneuploidy by massively parallel
sequencing." Prenatal Diagnosis 33(5): 409-415.
Gil et al 2015
Taylor-Philips et al 2016
Liao, C., A. H. Yin, et al. (2014). "Noninvasive prenatal diagnosis of common aneuploidies by semiconductor sequencing."
Proc Natl Acad Sci U S A 111(20): 7415-7420.
Mackie et al 2016
Mazloom, A. R., Z. Dzakula, et al. (2013). "Noninvasive prenatal detection of sex chromosomal aneuploidies by sequencing
circulating cell-free DNA from maternal plasma." Prenatal Diagnosis 33(6): 591-597.
Gil et al 2015
Nicolaides, K. H., T. J. Musci, et al. (2014). "Assessment of fetal sex chromosome aneuploidy using directed cell-free DNA
analysis." Fetal Diagnosis & Therapy 35(1): 1-6.
Gil et al 2015
Nicolaides, K. H., A. Syngelaki, et al. (2012). "Noninvasive prenatal testing for fetal trisomies in a routinely screened first-
trimester population." American Journal of Obstetrics & Gynecology 207(5): 374.e371-376.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Nicolaides, K. H., A. Syngelaki, et al. (2013). "Validation of targeted sequencing of single-nucleotide polymorphisms for non-
invasive prenatal detection of aneuploidy of chromosomes 13, 18, 21, X, and Y." Prenatal Diagnosis 33(6): 575-579.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Norton, M. E., H. Brar, et al. (2012). "Non-Invasive Chromosomal Evaluation (NICE) Study: results of a multicenter prospective
cohort study for detection of fetal trisomy 21 and trisomy 18." American Journal of Obstetrics & Gynecology 207(2):
137.e131-138.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Norton, M. E., B. Jacobsson, et al. (2015). "Cell-free DNA analysis for noninvasive examination of trisomy." New England
Journal of Medicine 372(17): 1589-1597 1589p.
Mackie et al 2016
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103
Study Review
Palomaki, G. E., C. Deciu, et al. (2012). "DNA sequencing of maternal plasma reliably identifies trisomy 18 and trisomy 13 as
well as Down syndrome: an international collaborative study." Genetics in Medicine 14(3): 296-305.
Gil et al 2015
Palomaki, G. E., E. M. Kloza, et al. (2011). "DNA sequencing of maternal plasma to detect Down syndrome: an international
clinical validation study." Genetics in Medicine 13(11): 913-920.
Gil et al 201
Taylor-Philips et al 2016
Pergament, E., H. Cuckle, et al. (2014). "Single-nucleotide polymorphism-based noninvasive prenatal screening in a high-
risk and low-risk cohort." Obstetrics and Gynecology 124(2 PART1): 210-218.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Porreco, R. P., T. J. Garite, et al. (2014). "Noninvasive prenatal screening for fetal trisomies 21, 18, 13 and the common sex
chromosome aneuploidies from maternal blood using massively parallel genomic sequencing of DNA." American Journal
of Obstetrics & Gynecology 211(4): 365.e361-365.e312 361p.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Quezada, M. S., M. M. Gil, et al. (2015). "Screening for trisomies 21, 18 and 13 by cell-free DNA analysis of maternal blood at
10-11 weeks' gestation and the combined test at 11-13 weeks." Ultrasound in Obstetrics & Gynecology 45(1): 36-41.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Sago, H., A. Sekizawa, et al. (2015). "Nationwide demonstration project of next-generation sequencing of cell-free DNA in
maternal plasma in Japan: 1-year experience." Prenatal Diagnosis 35(4): 331-336.
Taylor-Philips et al 2016
Samango-Sprouse, C., M. Banjevic, et al. (2013). "SNP-based non-invasive prenatal testing detects sex chromosome
aneuploidies with high accuracy." Prenatal Diagnosis 33(7): 643-649.
Gil et al 2015
Sehnert, A. J., B. Rhees, et al. (2011). "Optimal detection of fetal chromosomal abnormalities by massively parallel DNA
sequencing of cell-free fetal DNA from maternal blood." Clinical Chemistry 57(7): 1042-1049.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Shaw, S. W. S., C. Y. Chen, et al. (2013). "Non-invasive prenatal testing for whole fetal chromosomal aneuploidies: A multi-
center prospective cohort trial in Taiwan." Prenatal Diagnosis 33: 81.
Mackie et al 2016
Shaw, S. W. S., C. H. Hsiao, et al. (2014). "Noninvasive prenatal testing for whole fetal chromosomal aneuploidies: A
multicenter prospective cohort trial in Taiwan." Fetal Diagnosis and Therapy 35(1): 13-17.
Gil et al 2015
Taylor-Philips et al 2016
Song, Y., S. Huang, et al. (2015). "Non-invasive prenatal testing for fetal aneuploidies in the first trimester of pregnancy."
Ultrasound in Obstetrics & Gynecology 45(1): 55-60.
Gil et al 2015
Taylor-Philips et al 2016
104
Study Review
Song, Y., C. Liu, et al. (2013). "Noninvasive prenatal testing of fetal aneuploidies by massively parallel sequencing in a
prospective Chinese population." Prenatal Diagnosis 33(7): 700-706.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Sparks, A. B., C. A. Struble, et al. (2012). "Noninvasive prenatal detection and selective analysis of cell-free DNA obtained
from maternal blood: evaluation for trisomy 21 and trisomy 18." American Journal of Obstetrics & Gynecology 206(4):
319.e311-319.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Stumm, M., M. Entezami, et al. (2014). "Diagnostic accuracy of random massively parallel sequencing for non-invasive
prenatal detection of common autosomal aneuploidies: a collaborative study in Europe." Prenatal Diagnosis 34(2): 185-
191.
Gil et al 2015
Mackie et al 2016
Taylor-Philips et al 2016
Tong, Y. K., S. Jin, et al. (2010). "Noninvasive prenatal detection of trisomy 21 by an epigenetic-genetic chromosome-
dosage approach." Clin Chem 56(1): 90-98.
Mackie et al 2016
van den Oever, J. M., S. Balkassmi, et al. (2013). "Successful noninvasive trisomy 18 detection using single molecule
sequencing." Clinical Chemistry 59(4): 705-709.
Mackie et al 2016
van den Oever, J. M., S. Balkassmi, et al. (2012). "Single molecule sequencing of free DNA from maternal plasma for
noninvasive trisomy 21 detection." Clinical Chemistry 58(4): 699-706.
Mackie et al 2016
Verweij, E. J., M. De Boer, et al. (2012). "Non-invasive prenatal diagnosis of trisomy 21: Replacing invasive testing or
replacing screening?" American Journal of Obstetrics and Gynecology 206(1): S313.
Mackie et al 2016
Verweij, E. J., B. Jacobsson, et al. (2013). "European non-invasive trisomy evaluation (EU-NITE) study: a multicenter
prospective cohort study for non-invasive fetal trisomy 21 testing." Prenatal Diagnosis 33(10): 996-1001.
Gil et al 2015
Taylor-Philips et al 2016
Wax, J. R., A. Cartin, et al. (2015). "Noninvasive prenatal testing: impact on genetic counseling, invasive prenatal diagnosis,
and trisomy 21 detection." Journal of Clinical Ultrasound 43(1): 1-6.
Taylor-Philips et al 2016
Zhang, H., Y. Gao, et al. (2015). "Non-invasive prenatal testing for trisomies 21, 18 and 13: clinical experience from 146,958
pregnancies.[Erratum appears in Ultrasound Obstet Gynecol. 2015 Jul;46(1):130; PMID: 26134734]." Ultrasound in Obstetrics
& Gynecology 45(5): 530-538.
Mackie et al 2016
Taylor-Philips et al 2016
Zhou, Q., L. Pan, et al. (2014). "Clinical application of noninvasive prenatal testing for the detection of trisomies 21, 18, and
13: a hospital experience." Prenatal Diagnosis 34(11): 1061-1065.
Taylor-Philips et al 2016
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Study Review
Zimmermann, B., M. Hill, et al. (2012). "Noninvasive prenatal aneuploidy testing of chromosomes 13, 18, 21, X, and Y, using
targeted sequencing of polymorphic loci." Prenatal Diagnosis 32(13): 1233-1241.
Mackie et al 201
Taylor-Philips et al 2016
Level IV studies
Study
Dar, P., K. J. Curnow, et al. (2014). "Clinical experience and follow-up with large scale single-nucleotide polymorphism-based noninvasive prenatal aneuploidy
testing." American Journal of Obstetrics and Gynecology 211(5): 527.e521-527.e517.
Dobson LJ, Reiff ES, Little SE et al (2016) Patient choice and clinical outcomes following positive noninvasive prenatal screening for aneuploidy with cell-free DNA
(cfDNA). Prenat Diagn 36(5): 456-62.
Fairbrother, G., S. Johnson, et al. (2013). "Clinical experience of noninvasive prenatal testing with cell-free DNA for fetal trisomies 21, 18, and 13, in a general
screening population." Prenatal Diagnosis 33(6): 580-583.
Ke W-L, Zhao, W.-H., Wang, X.-Y., (2015) Detection of fetal cell-free DNA in maternal plasma for Down syndrome, Edward syndrome and Patau syndrome of high
risk fetus. Int J Clin Exp Med 8(6): 9525–30.
Lau, T. K., S. W. Cheung, et al. (2014). "Non-invasive prenatal testing for fetal chromosomal abnormalities by low-coverage whole-genome sequencing of
maternal plasma DNA: review of 1982 consecutive cases in a single center." Ultrasound in obstetrics & gynecology : the official journal of the International
Society of Ultrasound in Obstetrics and Gynecology 43(3): 254-264.
Lebo, R. V., R. W. Novak, et al. (2015). "Discordant circulating fetal DNA and subsequent cytogenetics reveal false negative, placental mosaic, and fetal mosaic
cfDNA genotypes." Journal of Translational Medicine 13(1).
Li, W. H., P. H. Wang, et al. (2015). "Noninvasive prenatal testing for fetal trisomy in a mixed risk factors pregnancy population." Taiwanese Journal of Obstetrics &
Gynecology 54(2): 122-125.
Oneda B, Steindl K, Masood R et al (2016) Noninvasive prenatal testing: more caution in counseling is needed in high risk pregnancies with ultrasound
abnormalities. Eur J Obstet Gynecol Reprod Biol 200: 72-5.
Persico N, Boito S, Ischia B et al (2016) Cell-free DNA testing in the maternal blood in high-risk pregnancies after first-trimester combined screening. Prenat Diagn
36(3): 232-6.
Radoi, V. E., C. L. Bohiltea, et al. (2015). "Cell free fetal DNA testing in maternal blood of Romanian pregnant women." Iranian Journal of Reproductive Medicine
13(10): 621-624.
106
Suzumori, N., T. Ebara, et al. (2014). "Non-specific psychological distress in women undergoing noninvasive prenatal testing because of advanced maternal
age." Prenatal Diagnosis 34(11): 1055-1060.
Taylor, J. B., V. Y. Chock, et al. (2014). "NIPT in a clinical setting: an analysis of uptake in the first months of clinical availability." Journal of Genetic Counseling
23(1): 72-78.
Wallerstein R, Jelks A, Garabedian MJ (2014) A new model for providing cell-free DNA and risk assessment for chromosome abnormalities in a public hospital
setting. J Pregnancy 2014: 962720.
Wang JC, Sahoo T, Schonberg S et al (2015a) Discordant noninvasive prenatal testing and cytogenetic results: a study of 109 consecutive cases. Genet Med
17(3): 234-6.
Wang L, Meng Q, Tang X et al (2015b) Maternal mosaicism of sex chromosome causes discordant sex chromosomal aneuploidies associated with noninvasive
prenatal testing. Taiwan J Obstet Gynecol 54(5): 527-31.
Yao, H., F. Jiang, et al. (2014). "Detection of fetal sex chromosome aneuploidy by massively parallel sequencing of maternal plasma DNA: initial experience in a
Chinese hospital." Ultrasound in Obstetrics & Gynecology 44(1): 17-24.
Zhang J & Zhang B (2016) Second-generation non-invasive high-throughput DNA sequencing technology in the screening of Down's syndrome in advanced
maternal age women. Biomed Rep 4(6): 715-18.
Other excluded studies
Study Reason for exclusion
Akaishi, R., T. Yamada, et al. (2014). "Prenatal genetic counseling and diagnosis in our institute: 2007-2014." Prenatal Diagnosis
34: 72-73.
Does not meet criteria for
grading (abstract)
Alcaine, M. J., C. Aulesa, et al. (2015). "Present situation of prenatal screening of chromosomopathies in Spain: SEQC survey
results 2013." Revista del Laboratorio Clinico 8(3): 138-148.
Not in English
Allyse, M., L. C. Sayres, et al. (2012). "Anticipated uptake of non-invasive prenatal testing among U.S. adults." Prenatal
Diagnosis 32: 25.
Does not meet criteria for
grading (abstract)
Anselem, O., S. Keroui, et al. (2015). Journal de Gynecologie Obstetrique et Biologie de la Reproduction. Not In English
Audibert, F., A. Gagnon, et al. (2011). "Prenatal screening for and diagnosis of aneuploidy in twin pregnancies." Journal of
Obstetrics & Gynaecology Canada: JOGC 33(7): 754-767. Does not answer research
question
Ayres, A. C., J. A. Whitty, et al. (2015). "A cost-effectiveness analysis comparing different strategies to implement noninvasive
prenatal testing into a down syndrome screening program." Obstetrical and Gynecological Survey 70(2): 63-65.
Does not meet criteria for
grading (abstract)
107
Study Reason for exclusion
Bayindir, B., L. Dehaspe, et al. (2015). "Noninvasive prenatal testing using a novel analysis pipeline to screen for all autosomal
fetal aneuploidies improves pregnancy management." European Journal of Human Genetics 23(10): 1286-1293.
Does not answer research
question
Beulen, L., J. P. C. Grutters, et al. (2013). "The implementation of noninvasive prenatal diagnosis in national health care: A
decision-analytic economic model." Prenatal Diagnosis 33: 69.
Does not meet criteria for
grading (abstract)
Beulen, L., J. P. C. Grutters, et al. (2015). "The consequences of implementing non-invasive prenatal testing in Dutch National
Health Care: A cost-effectiveness analysis: Editorial comment." Obstetrical and Gynecological Survey 70(3): 162-164
Editorial
Bianchi, D. W., S. Parsa, et al. (2015). "Fetal sex chromosome testing by maternal plasma DNA sequencing: Clinical laboratory
experience and biology." Obstetrics and Gynecology 125(2): 375-382.
Does not answer research
question
Bianchi, D. W., T. Prosen, et al. (2013). "Massively parallel sequencing of maternal plasma DNA in 113 cases of fetal nuchal
cystic hygroma." Obstetrics & Gynecology 121(5): 1057-1062.
Does not answer research
question
Cheung, S. W., A. Patel, et al. (2015). "Accurate description of DNA-based noninvasive prenatal screening." New England
Journal of Medicine 372(17): 1675-1677.
Letter
Chiu, R. W., K. C. Chan, et al. (2008). "Noninvasive prenatal diagnosis of fetal chromosomal aneuploidy by massively parallel
genomic sequencing of DNA in maternal plasma." Proceedings of the National Academy of Sciences of the United States of
America 105(51): 20458-20463.
Does not answer research
question
Courtney, E. and M. Sinosich (2014). "Consumers' experiences of and attitudes towards noninvasive prenatal testing in
Australia: The good, the bad and the ugly." Prenatal Diagnosis 34: 74.
Does not meet criteria for
grading (abstract)
Crimmins, S., X. Liu, et al. (2016). "Universal QUAD screen versus universal cell free DNA testing for Down's syndrome screening:
Cost-effectiveness analysis." American Journal of Obstetrics and Gynecology 214(1): S381-S382.
Does not meet criteria for
grading (abstract)
Dall'Amico, D. and E. Viora (2011). "Guidelines for prenatal screening of Down syndrome." Biochimica Clinica 35(3): 229-241. Not in English
Davidson, T., E. Iwarsson, et al. (2015). "Costs and cost-effectiveness of non-invasive prenatal diagnosis (NIPT) for detection of
trisomy 21 in Sweden." Value in Health 18(7): A352.
Does not meet criteria for
grading (abstract)
Deng, Y. H., A. H. Yin, et al. (2011). "Non-invasive prenatal diagnosis of trisomy 21 by reverse transcriptase multiplex ligation-
dependent probe amplification." Clinical Chemistry & Laboratory Medicine 49(4): 641-646.
Does not answer research
question (lab study)
Dondorp, W. J., G. M. W. R. De Wert, et al. (2015). "Non-invasive prenatal testing for aneuploidy and beyond: Challenges of
responsible innovation in prenatal screening-an ESHG/ASHG position statement." Human Reproduction 30: i107-i108. Does not meet criteria for
grading (abstract)
108
Study Reason for exclusion
Durst, J., A. Sutton, et al. (2014). "A cost-effective analysis of non-invasive prenatal testing for trisomy 21 in low-risk women."
American Journal of Obstetrics and Gynecology 210(1): S219.
Does not meet criteria for
grading (abstract)
Farrell, R. M., P. Agatisa, et al. (2015). "Women's perspectives on noninvasive prenatal testing for detection of sex
chromosome abnormalities and microdeletions." Obstetrics and Gynecology 125: 92S.
Does not meet criteria for
grading (abstract)
Fumagalli, S., A. Locatelli, et al. (2012). "Perception of risk and access to invasive prenatal diagnosis in women aged >35
years." Prenatal Diagnosis 32: 74-75.
Does not meet criteria for
grading (abstract)
Futch, T., J. Spinosa, et al. (2013). "Initial clinical laboratory experience in noninvasive prenatal testing for fetal aneuploidy
from maternal plasma DNA samples." Prenatal Diagnosis 33(6): 569-574.
does not answer research question
(lab study)
Gitsels-van der Wal, J. T., J. Manniën, et al. (2014). "Prenatal screening for congenital anomalies: exploring midwives'
perceptions of counseling clients with religious backgrounds." BMC Pregnancy and Childbirth 14: 237.
Does not answer research
question
Griffin, E., V. Lee, et al. (2015). "Cost effectiveness of first trimester aneuploidy screening in obese women of advanced
maternal age." American Journal of Obstetrics and Gynecology 212(1): S313-S314.
Does not meet criteria for
grading (abstract)
Hacker, F., E. Griffin, et al. (2015). "Role of genetic sonogram and NIPT after EIF detection: A cost-effectiveness analysis."
American Journal of Obstetrics and Gynecology 212(1): S171-S172.
Does not meet criteria for
grading (abstract)
Hernández-Gómez, M., E. Ramírez-Arroyo, et al. (2015). "Non invasive prenatal test (NIPT) in maternal blood by parallel
massive sequencing. initial experience in Mexican women and literature review." Ginecologia y Obstetricia de Mexico 83(5):
277-288.
Not in English
Higuchi, E. C., J. P. Sheldon, et al. (2016). "Non-invasive prenatal screening for trisomy 21: Consumers' perspectives." American
Journal of Medical Genetics, Part A 170(2): 375-385.
Does not answer research
question
Hill, M., C. Compton, et al. (2014). "Client views and attitudes to non-invasive prenatal diagnosis for sickle cell disease,
thalassaemia and cystic fibrosis." Journal of Genetic Counseling 23(6): 1012-1021.
Does not answer research
question
Hill, M., D. Wright, et al. (2014). "Evaluation of non-invasive prenatal testing (NIPT) for aneuploidy in an NHS setting: a reliable
accurate prenatal non-invasive diagnosis (RAPID) protocol." BMC Pregnancy & Childbirth 14: 229.
Does not meet criteria for
grading (protocol)
Hill, M., J. Fisher, et al. (2012). "Implementation of non-invasive prenatal diagnosis for Down's syndrome: What do women and
health professionals want?" Prenatal Diagnosis 32: 98.
Does not meet criteria for
grading (abstract)
Hill, M., J. Fisher, et al. (2013). "Women's and health professionals' preferences for prenatal tests for down syndrome: A discrete
choice experiment to contrast noninvasive prenatal diagnosis with current invasive tests." Obstetrical and Gynecological
Survey 68(3): 171-173.
Does not meet criteria for
grading (abstract and editorial)
109
Study Reason for exclusion
Hill, M., J. Johnson, et al. (2014). "Preferences for prenatal tests for Down syndrome: Comparing women and health
professionals from nine countries." Prenatal Diagnosis 34: 2-3.
Does not meet criteria for
grading (abstract)
Hill, M., S. Taffinder, et al. (2011). "Incremental cost of non-invasive prenatal diagnosis versus invasive prenatal diagnosis of
fetal sex in England." Prenatal Diagnosis 31(3): 267-273.
Does not answer research
question
Hui, L., M. Teoh, et al. (2014). "Clinical implementation of noninvasive prenatal testing for aneuploidy in Australia and New
Zealand." Prenatal Diagnosis 34: 56.
Does not meet criteria for
grading (abstract)
Hui, L., M. Teoh, et al. (2015). "Clinical implementation of noninvasive prenatal testing by Australian sonologists." BJOG: An
International Journal of Obstetrics and Gynaecology 122: 52.
Does not meet criteria for
grading (abstract)
Hulstaert, F., M. Neyt, et al. (2014) The non-invasive prenatal test (NIPT) for trisomy 21 ? health economic aspects. Does not meet criteria for
grading (abstract)
Jackson, J., B. Hamar, et al. (2014). "Nuchal translucency measurement plus non-invasive prenatal testing to screen for
aneuploidy in a community-based average-risk population." Ultrasound in Obstetrics & Gynecology 44(4): 491.
Letter
Jensen, T. J., T. Zwiefelhofer, et al. (2013). "High-throughput massively parallel sequencing for fetal aneuploidy detection from
maternal plasma." PLoS ONE [Electronic Resource] 8(3): e57381.
Does not answer research
question
Jin, Y., Z. Miao, et al. (2014). "Prenatal diagnosis of fetal chromosome aneuploidy by massively parallel genomic sequencing."
National Medical Journal of China 94(23): 1788-1790.
Not in English
Johnson, J., M. Pastuck, et al. (2013). "First-trimester Down syndrome screening using additional serum markers with and
without nuchal translucency and cell-free DNA." Prenatal Diagnosis 33(11): 1044-1049.
Does not answer research
question (no conclusions
relevant to current Australian
practice)
Kagan, K. O., D. Wright, et al. (2015). "First-trimester contingent screening for trisomies 21, 18 and 13 by fetal nuchal
translucency and ductus venosus flow and maternal blood cell-free DNA testing." Ultrasound in obstetrics & gynecology : the
official journal of the International Society of Ultrasound in Obstetrics and Gynecology 45(1): 42-47.
Does not answer research
question (no conclusions
relevant to current Australian
practice)
Kloza, E. M., P. K. Haddow, et al. (2015). "Evaluation of patient education materials: The example of circulating cell free DNA
testing for aneuploidy." Journal of Genetic Counseling 24(2): 259-266. Does not answer research
question
Larion, S., S. Warsof, et al. (2015). "Three year clinical experience with noninvasive prenatal testing in 3000 high risk cases in the
United States." Prenatal Diagnosis 35: 59.
Does not meet criteria for
grading (abstract)
110
Study Reason for exclusion
Lefkowitz, R. B., J. A. Tynan, et al. (2016). "Clinical validation of a noninvasive prenatal test for genomewide detection of fetal
copy number variants." American Journal of Obstetrics and Gynecology.
Potential conflict of interest
(industry study)
Lemery, D., Y. Ville, et al. (2010). "The new policy for Down' syndrome Screening in France: the Order of June 23, 2009." Revue
de médecine périnatale: 1-10. Not in English
Lewis, C. (2015). "Clinical implementation of non-invasive prenatal testing worldwide-results from a global survey." Prenatal
Diagnosis 35: 59-60.
Does not meet criteria for
grading (abstract)
Lewis, C. (2015). "Offering non-invasive prenatal testing for Down syndrome in a public health service clinical setting-can we
ensure maintenance of informed choice?" Prenatal Diagnosis 35: 19-20.
Does not meet criteria for
grading (abstract)
Lewis, C., M. Hill, et al. (2013). "Noninvasive prenatal testing for aneuploidy-a survey of the UK public's views." Prenatal
Diagnosis 33: 70-71.
Does not meet criteria for
grading (abstract)
Lewis, C., M. Hill, et al. (2014). "Offering NIPT for Down syndrome in a national health service clinical setting: UK patient
experiences." Prenatal Diagnosis 34: 82.
Does not meet criteria for
grading (abstract)
Li SW, Barrett AN, Gole L et al (2015) The assessment of combined first trimester screening in women of advanced maternal
age in an Asian cohort. Singapore Medical Journal 56(01): 47-52.
Does not answer research
question
Li, B., S. Pena, et al. (2014). "Trend of invasive procedure rates in women following positive first trimester combined screening
(FTCS) before and after the introduction of noninvasive prenatal testing (NIPT)." American Journal of Obstetrics and
Gynecology 210(1): S91-S92.
Does not meet criteria for
grading (abstract)
Li, G. and M. Allyse (2014). "Difference in attitudes on noninvasive prenatal testing in China and the United States." Prenatal
Diagnosis 34: 81.
Does not meet criteria for
grading (abstract)
Lim, J. H., S. Y. Kim, et al. (2011). "Non-invasive epigenetic detection of fetal trisomy 21 in first trimester maternal plasma." PLoS
ONE [Electronic Resource] 6(11): e27709.
Does not answer research
question
Liu, J., H. Wang, et al. (2015). "Application of next-generation DNA sequencing for prenatal testing of fetal chromosomal
aneuploidies." Chinese Journal of Medical Genetics 32(4): 533-537.
Not in English
Ma, J., H. Pan, et al. (2015). "Perspective study of non-invasive prenatal testing using cell-free fetal DNA in high-risk
population." National Medical Journal of China 95(11): 849-852.
Not in English
Madankumar, R., K. Brown, et al. (2014). "Assessing obstetricians knowledge on non invasive prenatal screening."
Reproductive Sciences 21(3): 258A.
Does not meet criteria for
grading (abstract)
111
Study Reason for exclusion
Maxwell, S. J., J. E. Dickinson, et al. (2015). "Knowledge of noninvasive prenatal testing among pregnant women." Medical
Journal of Australia 203(2): 76.
Letter
McCullough, R. M., E. A. Almasri, et al. (2014). "Non-invasive prenatal chromosomal aneuploidy testing - Clinical experience:
100,000 clinical samples." PLoS ONE 9(10).
Does not answer research
question
Mundy, L. and J. E. Hiller (2008) Non-invasive prenatal diagnostic test for Down's Syndrome (Structured abstract). Does not meet criteria for
grading (abstract)
Mundy, L. and J. E. Hiller (2009) Non-invasive prenatal diagnostic test for trisomy-21 (Down's Syndrome) (Structured abstract). Does not meet criteria for
grading (abstract)
Nicolaides, K. H., A. Syngelaki, et al. (2013). "Noninvasive prenatal testing for fetal trisomies in a routinely screened first-
trimester population." Obstetrical and Gynecological Survey 68(3): 173-175.
Does not meet criteria for
grading (abstract)
Nicolaides, K. H., A. Syngelaki, et al. (2014). "First-trimester contingent screening for trisomies 21, 18 and 13 by biomarkers and
maternal blood cell-free DNA testing." Fetal Diagnosis & Therapy 35(3): 185-192.
Does not answer research
question
Nicolaides, K. H., D. Wright, et al. (2013). "First-trimester contingent screening for trisomy 21 by biomarkers and maternal blood
cell-free DNA testing." Ultrasound in Obstetrics & Gynecology 42(1): 41-50.
Does not answer research
question
Nicolaides, K. H., T. J. Musci, et al. (2014). "Assessment of fetal sex chromosome aneuploidy using directed cell-free DNA
analysis." Obstetrical and Gynecological Survey 69(5): 249-250.
Does not meet criteria for
grading (abstract)
Norton, M. E., B. Jacobsson, et al. (2015). "Cell-Free DNA Analysis for Noninvasive Examination of Trisomy." Obstetrical and
Gynecological Survey 70(8): 483-484.
Does not meet criteria for
grading (abstract)
Norton, M. E., L. L. Jelliffe-Pawlowski, et al. (2014). "Chromosome abnormalities detected by current prenatal screening and
noninvasive prenatal testing." Obstetrics & Gynecology 124(5): 979-986.
Does not answer research
question
Odibo, A., A. Cahill, et al. (2013). "Introducing non-invasive prenatal testing (NIPT) into screening paradigms for trisomy 21
(T21): Is it cost-effective?" American Journal of Obstetrics and Gynecology 208(1): S242-S243.
Does not meet criteria for
grading (abstract)
Ohno M & Caughey A (2013) The role of noninvasive prenatal testing as a diagnostic versus a screening tool--a cost-
effectiveness analysis. Prenat Diagn 33(7): 630-5.
Does not answer research
question
Ohno, M., A. Allen, et al. (2013). "A cost-effectiveness analysis of using non-invasive prenatal testing as a screening tool for
Down syndrome." American Journal of Obstetrics and Gynecology 208(1): S235.
Does not meet criteria for
grading (abstract)
112
Study Reason for exclusion
Palomaki, G. E., E. E. Eklund, et al. (2015). "Evaluating first trimester maternal serum screening combinations for Down
syndrome suitable for use with reflexive secondary screening via sequencing of cell free DNA: High detection with low rates
of invasive procedures." Prenatal Diagnosis 35(8): 789-796.
Does not answer research
question
Papageorgiou, E. A., A. Karagrigoriou, et al. (2011). "Fetal-specific DNA methylation ratio permits noninvasive prenatal
diagnosis of trisomy 21." Nature Medicine 17(4): 510-513.
Does not answer research
question
Pérez-Pedregosa, J., B. Paredes Ros, et al. (2015). "Non-invasive prenatal screening for aneuploidy through analysis of cell-
free fetal DNA from maternal blood." Progresos de Obstetricia y Ginecologia 58(3): 113-117.
Not in English
Petersen, O. B., I. Vogel, et al. (2014). "Potential diagnostic consequences of applying noninvasive prenatal testing:
Population-based study from a country with existing first-trimester screening." Obstetrical and Gynecological Survey 69(6):
321-323.
Editorial
Polish Gynaecological, S. and S. Polish Human Genetics (2015). "[Cell-free fetal DNA testing in prenatal genetic screening.
Polish Gynaecological Society and Polish Human Genetics Society guidelines]." Ginekologia Polska 86(12): 966-969. Not in English
Reiff ES, Little SE, Dobson L et al (2016) What is the role of the 11- to 14-week ultrasound in women with negative cell-free DNA
screening for aneuploidy? Prenat Diagn 36(3): 260-5.
Does not answer research
question
Rose, N. C., D. Lagrave, et al. (2013). "The impact of utilization of early aneuploidy screening on amniocenteses available for
training in obstetrics and fetal medicine." Prenatal Diagnosis 33(3): 242-244.
Does not answer research
question
Ryan, A., N. Hunkapiller, et al. (2016). "Validation of an Enhanced Version of a Single-Nucleotide Polymorphism-Based
Noninvasive Prenatal Test for Detection of Fetal Aneuploidies." Fetal Diagnosis and Therapy.
Potential conflict of interest
(industry study)
Sánchez-Usabiaga, R. A., M. Aguinaga-Ríos, et al. (2015). "Clinical implementation of non-invasive prenatal study for
detecting aneuploidies by fetal DNA based on single nucleotide polymorphisms: Two years in Mexico." Ginecologia y
Obstetricia de Mexico 83(4): 220-231.
Not in English
Sayres, L. C., M. Allyse, et al. (2012). "Integrating stakeholder perspectives into the translation of cell-free fetal DNA testing for
aneuploidy." Genome Medicine 4(6).
Does not answer research
question
Sbu (2014) Non-invasive prenatal test for Down's syndrome (Project record). Does not meet criteria for
grading (project record)
Sekhon, R., E. Lee, et al. (2015). "Non-invasive prenatal testing (NIPT): Evaluating patient preference of antenatal
investigations in high risk women." Journal of Medical Imaging and Radiation Oncology 59 (Suppl 1): 9.
Does not meet criteria for
grading (abstract)
113
Study Reason for exclusion
Sharma, P., A. Metcalfe, et al. (2015). "Women's understanding of non-invasive prenatal testing based on cell free DNA versus
first trimester combined screening." Prenatal Diagnosis 35: 106.
Does not meet criteria for
grading (abstract)
Shengmou, L., C. Min, et al. (2014). "Effects, safety and cost-benefit analysis of Down syndrome screening in first trimester."
Zhonghua fu chan ke za zhi 49(5): 325-330.
Not in English
Silcock, C., L. S. Chitty, et al. (2012). "Will the introduction of non-invasive prenatal diagnosis for Down's syndrome influence
informed choice?" Prenatal Diagnosis 32: 25-26.
Does not meet criteria for
grading (abstract)
Sinkey, R. G. and A. O. Odibo (2016). "Cost-Effectiveness of Old and New Technologies for Aneuploidy Screening." Clinics in
Laboratory Medicine.
Narrative review
Song K, Musci TJ, Caughey AB (2013) Clinical utility and cost of non-invasive prenatal testing with cfDNA analysis in high-risk
women based on a US population. J Matern Fetal Neonatal Med 26(12): 1180-5.
Potential conflict of interest
(industry study)
Stokowski R, Wang E, White K et al (2015) Clinical performance of non-invasive prenatal testing (NIPT) using targeted cell-free
DNA analysis in maternal plasma with microarrays or next generation sequencing (NGS) is consistent across multiple
controlled clinical studies. Prenat Diagn 35(12): 1243-6.
Potential conflict of interest
(industry study)
Strah, D., P. Ovniek, et al. (2015). "Non-invasive prenatal cell-free fetal DNA testing for down syndrome and other
chromosomal abnormalities." Zdravniski Vestnik 84(11): 727-733.
Does not answer research
question (no conclusions
relevant to current Australian
practice)
Stumm, M., M. Entezami, et al. (2012). "Non-invasive prenatal detection of trisomy 21 using massively parallel sequencing: A
collaborative study in Europe." Prenatal Diagnosis 32: 63-64.
Does not meet criteria for
grading (abstract)
Stumm, M., M. Entezami, et al. (2012). "Noninvasive prenatal detection of chromosomal aneuploidies using different next
generation sequencing strategies and algorithms." Prenatal Diagnosis 32(6): 569-577.
Does not answer research
question
Susman, M., J. L. Halliday, et al. (2011). "Understanding women's decisions about prenatal diagnosis for chromosome
abnormalities." Twin Research and Human Genetics 14(4): 378.
Does not meet criteria for
grading (abstract)
Sutton, A., J. Durst, et al. (2014). "Non-invasive prenatal testing for trisomy 21 in high-risk women: A cost-effectiveness analysis."
American Journal of Obstetrics and Gynecology 210(1): S67.
Does not meet criteria for
grading (abstract)
Swaney, P., E. Hardisty, et al. (2014). "Attitudes and knowledge of Maternal-Fetal Medicine fellows regarding noninvasive
prenatal testing (NIPT)." American Journal of Obstetrics and Gynecology 210(1): S254-S255.
Does not meet criteria for
grading (abstract)
114
Study Reason for exclusion
Taneja, P. A., H. L. Snyder, et al. (2016). "Noninvasive prenatal testing in the general obstetric population: Clinical
performance and counseling considerations in over 85000 cases." Prenatal Diagnosis 36(3): 237-243.
Potential conflict of interest
(industry study)
Tonk, V. S. and G. N. Wilson (2016). "Inaccuracy of non-invasive prenatal screening demands cautious counsel and follow-
up." American Journal of Medical Genetics, Part A 170(4): 1086-1087.
Letter
Tynan, J. A., S. K. Kim, et al. (2016). "Application of risk score analysis to low-coverage whole genome sequencing data for
the noninvasive detection of trisomy 21, trisomy 18, and trisomy 13." Prenatal Diagnosis 36(1): 56-62.
Potential conflict of interest
(industry study)
Van Opstal D, Srebniak MI, Polak J et al (2016) False Negative NIPT Results: Risk Figures for Chromosomes 13, 18 and 21 Based
on Chorionic Villi Results in 5967 Cases and Literature Review. PLoS One 11(1): e0146794.
Does not answer research
question
Van Schendel, R., L. Page-Christiaens, et al. (2015). "Experiences of high-risk pregnant women who were offered a choice
between non-invasive prenatal testing, invasive testing or no follow-up test." Prenatal Diagnosis 35: 18-19.
Does not meet criteria for
grading (abstract)
Van Wymersch, D. and G. Gilson (2015). "Introduction of noninvasive prenatal testing for fetal trisomies: preliminary results and
consequences on invasive samplings." Bulletin de la Societe des Sciences Medicales du Grand-Duche de Luxembourg(1): 65-
72.
Not in English
Verweij, E. J. J., D. Oepkes, et al. (2012). "Changed attitude towards termination of pregnancy for trisomy 21 with non-invasive
prenatal diagnosis." Prenatal Diagnosis 32: 26.
Does not meet criteria for
grading (abstract)
Verweij, E. J. J., D. Oepkes, et al. (2012). "Non-invasive prenatal detection of trisomy 21: What women want and what they
want to pay." Prenatal Diagnosis 32: 101.
Does not meet criteria for
grading (abstract)
Walker BS, Jackson BR, LaGrave D et al (2015a) A cost-effectiveness analysis of cell free DNA as a replacement for serum
screening for Down syndrome. Prenat Diagn 35(5): 440-6.
Does not answer research
question (integrated screening)
Wang, S. J., Z. Y. Gao, et al. (2012). "[Value of detection of cell-free fetal DNA in maternal plasma in the prenatal diagnosis of
chromosomal abnormalities]." Zhonghua fu chan ke za zhi 47(11): 808-812.
Not in English
Wang, S., Z. Gao, et al. (2014). "Detection of fetal chromosomal aneuploidy in pregnant women at advanced maternal age
during the first trimester." Nan Fang Yi Ke Da Xue Xue Bao = Journal of Southern Medical University 34(5): 655-658.
Not in English
Wax, J. R., R. Chard, et al. (2015). "Noninvasive prenatal testing: the importance of pretest trisomy risk and posttest predictive
values." American Journal of Obstetrics & Gynecology 212(4): 548-549.
Letter
Wray, A., H. Landy, et al. (2015). "Physician utilization and interpretation of non-invasive prenatal screening (NIPS)." Prenatal
Diagnosis 35: 109.
Does not meet criteria for
grading (abstract)
115
Study Reason for exclusion
Wright, D., A. Wright, et al. (2015). "A unified approach to risk assessment for fetal aneuploidies." Ultrasound in Obstetrics &
Gynecology 45(1): 48-54.
Does not answer research
question
Yu, S. C., K. C. Chan, et al. (2014). "Size-based molecular diagnostics using plasma DNA for noninvasive prenatal testing."
Proceedings of the National Academy of Sciences of the United States of America 111(23): 8583-8588.
Does not answer research
question
116
2. Are there specific issues for Aboriginal and Torres Strait Islander women and rural and
remote populations?
No studies identified
117
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