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DISSERTATION
COMPARISON BETWEEN PLACENTAL ALPHA
MICROGLOBULIN 1 (AMNISURE) RAPID IMMUNOASSAY AND
STANDARD CLINICAL METHOD FOR DIAGNOSIS OF PREMATURE
RUPTURE OF MEMBRANES IN IDO EKITI
INSTITUTION
DEPARTMENT OF OBSTETRICS AND GYNAECOLOGY
FEDERAL TEACHING HOSPITAL IDO EKITI
EKITI STATE
INVESTIGATOR
DAMILOLA IFARINOLA
MBBS ILORIN
A DISSERTATION SUBMITTED TO THE NATIONAL POSTGRADUATE
MEDICAL COLLEGE OF NIGERIA AS PART FULFILLMENT FOR THE
PART II FELLOWSHIP EXAMINATION IN THE FACULTY OF
OBSTETRICS AND GYNAECOLOGY.
MAY 2017
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DECLARATION BY THE INVESTIGATOR
I hereby declare that this study was carried out at the department of
Obstetrics and Gynaecology of the Federal Teaching Hospital, Ido-Ekiti,
Ekiti State. I also affirm that the study has not been submitted for award of
fellowship or publication in any journal.
DAMILOLA IFARINOLA
………………………..................
Name and Signature of Investigator
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SUPERVISORS’ CERTIFICATION
We hereby certify that Dr.Damilola Ifarinola of the Department of
Obstetrics and Gynaecology, Federal Teaching Hospital, Ido-Ekiti carried
out this work under our supervision.
Supervisor:______________________________
DR O.E ADEWARA
Department of Obstetrics and Gynaecology, Federal Teaching Hospital, Ido-
Ekiti, Ekiti State; Nigeria
Supervisor:______________________________
DR I.O ADEBARA
Department of Obstetrics and Gynaecology, Federal Teaching Hospital, Ido-
Ekiti, Ekiti State; Nigeria
Head of Department:________________________
DR O.E ADEWARA
Department of Obstetrics and Gynaecology, Federal Teaching Hospital, Ido-
Ekiti, Ekiti State; Nigeria
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TABLE OF CONTENT
Title page .....................................................................................................I
Declaration by investigator .........................................................................II
Supervisor’s certification...............................................................................III
Table of content............................................................................................IV
Abbreviations ..............................................................................................VI
Abstract .......................................................................................................VII
CHAPTER ONE: INTRODUCTION AND JUSTIFICATION
1.1 Introduction..........................................................................................1
1.2 Justification for study...........................................................................6
CHAPTER TWO: LITERATURE REVIEW
2.1Background ..........................................................................................8
2.2 Pathophysiology of premature rupture of membranes.........................11
2.3 Diagnosis of premature of membrane..................................................12
2.4 Placenta alpha microglobulin 1............................................................14
2.5 Management of PROM........................................................................15
CHAPTER THREE: AIMS, OBJECTIVES AND HYPOTHESIS
3.1 Aims and objectives.............................................................................17
3.2 Hypothesis...........................................................................................17
CHAPTER FOUR: MATERIALS AND METHODOLOGY
4.1 Description of study area....................................................................18
4.2 Study location.....................................................................................18
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4.3 Study duration.....................................................................................18
4.4 Study design.........................................................................................18
4.41Sample size determination..................................................................19
4.42 Study procedure.................................................................................19
4.51 Inclusion criteria................................................................................21
4.52 Exclusion criteria...............................................................................22
4.6 Data analysis........................................................................................22
4.7Study duration.......................................................................................22
4.8 Ethical consideration............................................................................22
CHAPTER FIVE: RESULTS……………………………………………..25
CHAPTER SIX: DISCUSSION……..……………………………………36
CHAPTER SEVEN: CONCLUSION AND RECOMMENDATION
7.1 CONCLUSION …………………………………..…………………43
7.2 RECOMMENDATION……………………………………………..43
7.3LIMITATIONS………………………………………………………44
WORK PLAN…………………………………………………………….44
REFERENCES .......................................................................................45
APPENDIX 1(PROFORMA).....................................................................52
APPENDIX II(CONSENT FORM) ...........................................................56
INFORMATION TO PARTICIPANTS………………………………….57
ETHICAL APPROVAL.............................................................................58
AMNISURE LEAFLETS...........................................................................59
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ABBREVIATIONS
ACOG...................American College of Obstetricians and Gynaecologist
AFI………………Amniotic Fluid Index
FDA......................Food and Drug Administration
FMC.....................Federal Medical Centre Ido Ekiti .
FTH......................Federal Teaching Hospital Ido Ekiti.
LAUTECH...........Ladoke Akintola University
NPV……………..Negative Predictive Value
PAMG 1...............Placenta Alpha Microglobulin 1
PPROM................Preterm Premature Rupture of Membranes
PPV………………Positive Predictive Value
PROM..................Premature Rupture of Membranes.
RCOG..................Royal College of Obstetrics and Gynaecology
ROM....................Rupture of Membranes
US…………….Ultrasonography
WHO....................World Health Organisation
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ABSTRACT
Background: Premature rupture of membranes is an important obstetric
condition that poses significant risk to the wellbeing of the foetus in-utero,
constituting a source of morbidity and possible mortality if not appropriately
diagnosed and managed. Approximately 8% to 10% of term pregnancies will
experience spontaneous rupture of membranes prior to the onset of labour. An
accurate diagnosis with prompt and correct intervention is of utmost importance
in the management of rupture of membranes especially in preterm gestation.
The search for accuracy and increased specificity in diagnosis of premature
rupture of membrane is an ongoing process.
Objective: To determine the accuracy of placental alpha micro globulin
1(PAMG 1) Amnisure ROM in diagnosing presence of amniotic fluid in
cervicovaginal secretions and hence diagnose rupture of fetal membranes.
To compare Amnisure ROM with standard clinical assessment in diagnosing
rupture of fetal membranes.
To determine and compare the sensitivity and specificity of amnisure ROM and
standard clinical assessment in diagnosis of premature rupture of membranes.
Methodology: All pregnant women with symptoms suggestive of premature
rupture of membrane such as trickling or gush of fluid per vagina were
evaluated using the amnisure ROM kit and standard clinical evaluation and
findings noted on appropriate proforma.
viii
Data analysis: Data collected using the proforma was subjected to statistical
analysis using SPSS version 18.
Results: A total number of 64 patients were recruited , the mean age was 29.6 ±
3.4years.The mean gravidity was 3.0 ± 1.4, with a mean parity of 1.3 ± 1.3
while the mean gestational age at presentation was 37.2 ± 2.4 weeks. The
amnisure test and standard clinical assessment were positive in 45(70.3%)
patients and negative in 11(17.2%) patients. A total of 52(81.2%) patients had
positive results following amnisure test while 46(71.2%) had positive results
following standard clinical assessment. There was disparity in test results in
8(12.5%) patients, 7(10.9%) of which were positive in the amnisure test and
negative in the standard clinical assessment while 1(1.6%) patient was negative
following amnisure assay and positive following standard clinical assessment.
The patients with true positive result were 54(84.3%), true negative 10(15.6%).
The sensitivity, specificity, positive predictive value and negative predictive
value were 96.3%, 100%, 100% and 83.3% following amnisure test and 84.3%,
100%, 100% and 55.6% following standard clinical assessment for the
diagnosis of premature rupture of membranes.
Conclusion: Placental alpha-microglobulin-1 immunoassay is a rapid and
accurate method for confirming the diagnosis of rupture of membrane. It was
superior to conventional standard diagnostic methods
ix
x
CHAPTER ONE
INTRODUCTION
Premature (pre-labour) rupture of membranes is defined as spontaneous rupture
of foetal membranes before the onset of labour at any gestational age1, 2.
Premature rupture of membranes is an important obstetric condition that poses
significant risk to the wellbeing of the foetus in-utero, constituting a source of
morbidity and possible mortality if not appropriately diagnosed and
managed. About one in five women will present during pregnancy with
suspicion of premature rupture of membrane1.
Approximately 8% to 10% of term pregnancies will experience spontaneous
rupture of membranes prior to the onset of uterine activity1-4. Preterm premature
rupture of membranes defined as rupture of foetal membranes prior to 37 weeks
of gestation complicates 2% to 4% of all singleton and 7% to 20% of twin
pregnancies 1-5 and occurs in 25-30% of all preterm births in which it accounts
for 18-20% of prenatal deaths in the United States of America1-5.
An accurate diagnosis with prompt and correct intervention is of utmost
importance in the management of rupture of membranes especially in preterm
gestation. Clinicians have to weigh between risk of prolonging the pregnancy
and risk of neonatal morbidity from abruptio placenta, cord prolapse,
chorioamnionitis and preterm delivery. Failure to ascertain the correct diagnosis
would result in either failure to initiate proper treatment or would lead to
unnecessary interventions such as hospitalization and inappropriate use of
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antibiotics and antenatal corticosteroids, as well as induction of labour. This
will lead to increased maternal and fetal morbidity and mortality which in turn
leads to higher health care cost .Attempts at accurate diagnosis and management
of premature rupture of membranes is not new in obstetric practice 6-10, it has
been evolving over the years with continued contribution from obstetricians all
over the world aimed at preventing attendant morbidities and mortalities while
minimising cost7,8. Accurate diagnosis of premature rupture of membrane is
froth with challenges because there are other clinical differentials that present
with drainage of fluid par vagina other than rupture of membranes. Some close
differentials include urinary incontinence, leucorrhea of pregnancy and
infections. The standard clinical diagnosis of premature rupture of membranes
is by visually ascertaining egress of fluid from the cervical os and or pooling of
fluid in the posterior fornix at a sterile speculum examination particularly in low
resource settings because of the lack of capacity for specific identification of the
fluid as amniotic fluid7-10. Differentiating amniotic fluid from other fluid
drainage has over the years utilized characteristic properties of the amniotic
fluid which sometimes distinguish amniotic fluid to a certain extent but not with
the desired degree of specificity, precision and accuracy. The desire to increase
the accuracy, sensitivity and specificity in diagnosis has been the driving force
behind many intellectual discourse and research over the years and this has
helped to increasingly identify substances in amniotic fluid and properties of
amniotic fluid that differentiate it from other differentials thereby increasing
xii
diagnostic accuracy. According to the American College of Obstetricians and
Gynecologists (ACOG) Practice Bulletin Premature Rupture of
Membranes (2007) 1 and the Royal College of Obstetricians and Gynaecologists
(RCOG) Guideline Preterm Prelabour Rupture of Membranes (2006), the
diagnosis of Premature rupture of membranes is based primarily on the
patient's history and physical examination. Patients often report a sudden gush
of fluid or continued leakage of fluid. Sterile speculum examination provides a
visual inspection of fluid and an opportunity to inspect for cervicitis and
umbilical cord prolapse, cervical dilation and effacement, and to obtain cultures
as appropriate.
Digital cervical examinations are avoided due to the increase risk of infection,
reduction in the latency period and stimulation of uterine contractions and it
will not give significant additional information to the speculum examination
(unless the patient is in active labour or it is intended to facilitate delivery
through stimulation of contractions).
Diagnostic methods using nitrazine paper and determination of ferning
(arborization) have sensitivities approaching 90%. The pH of vaginal secretions
is generally 4.5 to 6.0, whereas amniotic fluid usually has a pH of 7.1 to 7.37,8;
however, false-positive results may occur as the result of contamination with
blood, urine, semen, alkaline antiseptics, or bacterial vaginosis and false-
negative results can occur with prolonged leakage and minimal residual fluid.
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In unusual cases in which the diagnosis remains unclear after physical
examination, ultrasonography may be helpful. When ultrasonography is
inconclusive, transabdominal instillation of indigo carmine dye followed by
observation for passage of blue fluid from the vagina will confirm ROM
unequivocally. Management of rupture of membranes hinges on knowledge of
gestational age and evaluation of the relative risks of preterm birth versus
intrauterine infection, abruptio placentae, and cord accident that could occur
with expectant management.
Placental alpha microglobin1 was isolated in 1975 from amniotic fluid by D
Petrunin and was originally referred to as specific alpha 1 globulin of
placenta9-12. Placenta alpha micoglobulin-1 is present in the blood, amniotic
fluid and cervico-vaginal discharge of pregnant women9.The concentration is
several thousand magnitudes higher after ruptured fetal membranes than that
which is found in vaginal discharge in pregnant women when the fetal
membrane is intact. PAMG-1 has been found to be present in amniotic fluid
throughout all three trimesters of pregnancy9-12.The AmniSure ROM (Rupture
of Membranes) test received Food and Drug Administration marketing
clearance in 2003 and is a rapid, non-instrumented qualitative
immunochromatographic test for in-vitro detection of amniotic fluid in vaginal
secretion of pregnant women. AmniSure detects PAMG-1 (placental alpha-1
microglobulin) protein marker of the amniotic fluid in vaginal secretions and is
intended to aid in the detection of rupture of membrane in pregnant women
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greater than 34 weeks gestation with signs, symptoms or complaints suggestive
of rupture of membranes9-12. On January 9 2009 the FDA cleared indication for
use was modified to remove the specification that the device is for use in
women greater than 34 weeks gestation.
The Amnisure ROM (rupture of fetal membrane) test is a rapid, non-
instrumented, qualitative immunochromatographic test for the in vitro detection
of amniotic fluid in vaginal secretions of pregnant women. Amnisure detects
PAMG-1 protein marker of the amniotic fluid in vaginal secretions. The test is
for use by health care professionals to aid in the detection of ROM when
patients report symptoms or complaints suggestive of ROM (FDA, 2009).
The evidence basis for this change in FDA labelling was provided as the
expected values were determined in literature studies and from research
performed by the sponsor; concentration of PAMG-1 in cervical and vaginal
secretions of pregnant women without complications was measured and ranged
from 0.05 and 0.22 ng/mL9. PAMG-1 concentrations in the amniotic fluid is
between 2,000 and 25,000 ng/mL range. This sharp difference in the measured
range of placental alpha microglobulin 1 is considered an important factor that
can suggest presence of amniotic fluid and hence rupture of fetal membranes.
Other immunochromatographic tests evaluating biochemical substances such as
alpha fetoprotein, placenta protein 12, fetal fibronectin, HCG,prolactin, insulin
growth factor binding protein in cervical secretions for the purpose of diagnosis
xv
of premature rupture of membranes have also been considered by different
researchers.
JUSTICATION FOR THE STUDY
The quest for accuracy in diagnosing premature rupture of membranes in order
to facilitate subsequent appropriate management is an on-going process. A lot
has been done in this regard but considering the grave consequence of the
inappropriately diagnosed cases, the benefits of increased accuracy in diagnosis
and management is worth investing. The cost of a wrong diagnosis and
inappropriate management of premature rupture of membranes cannot be
overemphasised because of the magnitude of effect on morbidity and mortality
of the newborn from prematurity, infections with the attendant complications
and possibility of jeopardy to the future reproductive capability of the woman
from ascending infections. Diagnosis of ruptured fetal membranes is of crucial
importance at any period in a pregnancy for prompt hospitalization and for
timely and proper treatment. The diagnosis of PROM is especially challenging
in equivocal cases with no pooling of fluid observed in the posterior fornix at
the speculum examination. The use of ultrasound could also be equivocal
because of the wide range of normal amniotic fluid index.
According to Di Renzo GC et al in 2011, evaluation of ferning, nitrazine, and/or
ultrasound has shown that they add little, if anything, to speculum examination
alone and that none of them are as accurate as tests based on biochemical
markers we believe that there is little to merit their use in modern practice6,11-14.
xvi
It is therefore important to critically evaluate the possibility of increasing
accuracy and promptness in diagnosis of premature rupture of membranes while
attempting to reduce the invasiveness of procedures aimed at achieving this
goal.
In a prospective observational study performed in consecutive patients with
signs or symptoms of rupture of membranes at Seoul National University
Hospital from March 2005 to February 2006, Of 184 patients (11-42 weeks of
gestation), rupture of membranes was diagnosed at initial presentation in 76%
(139 of 184) using conventional clinical assessment and 88% (161 of 184) using
placental alpha-microglobulin-1 immunoassay. Follow-up confirmed that a total
of 159 of 183 patients (87%) had rupture of membranes at their initial
presentations12.
A local study to compare the diagnostic accuracy and or advantages of the use
of amnisure with the traditional clinical diagnosis using routine observation of
egress and or pooling of amniotic fluid in Federal Teaching Hospital Ido Ekiti
appears an appealing task that can contribute to the body of knowledge. This
study will among other things seek to confirm or refute the facts identified in
the Seoul study and other similar studies.
xvii
CHAPTER TWO
LITERATURE REVIEW
2.1BACKGROUND
The amnion is a bilayered membranous sac which surrounds and protects the
embryo, enclosing the amniotic cavity which contains amniotic fluid14. The
amniotic cavity is roofed in by the amniotic ectoderm, comprised of a single
stratum of flattened, ectodermal cells, and its floor consists of the prismatic
ectoderm of the embryonic disc 14,15. The amniotic ectoderm is covered by a thin
layer of mesoderm, which is continuous with that of the somatopleure and is
connected, via the body-stalk, to the mesodermal lining of the chorion 14,15. The
somatopleure which is a combination of ectoderm and mesoderm, gives rise to
both the amniotic and chorionic membranes; the ectodermal tissue supplies
functioning epithelial cells, and the mesoderm generates the essential blood
supply to and from this epithelium16-20. The amniotic membrane forms as a layer
of epiblast cells expands towards the embryonic pole and differentiates into a
thin membrane that separates the new cavity from the cytotrophoblast and
eventually constitutes the lining of the amnion appears on day 8 of human
development20. The amniotic fold is formed when the somatopleure folds
upward and at the point of constriction where the primitive digestive tube of the
embryo joins the yolk sac, the fold tips meet and fuse over the dorsal aspect of
xviii
the embryo, forming the amniotic cavity19,20. The two layers of the fold then
become completely separated, the inner forming the amnion, the outer the false
amnion or serosa20, 21. The space between the amnion and the serosa constitutes
the extra-embryonic coelom 20 .When first formed, the amnion is in contact with
the body of the embryo, but about the fifth week of gestation, amniotic fluid
begins to accumulate within it20,21. This fluid increases in quantity and causes
the amnion to expand and to ultimately adhere to the inner surface of the
chorion 20, 21. The amniotic fluid increases in quantity allowing free movements
of the fetus during the later stages of pregnancy, and protects it by diminishing
the risk of injury17,18,19.
The membranes surrounding the amniotic cavity are composed of the amnion
and the chorion, which are closely adherent layers consisting of several cell
types, including epithelial cells, mesenchymal cells, and trophoblast cells,
embedded in a collagenous matrix16-19. The human amnion is composed of five
distinct layers14,15. It contains no blood vessels or nerves; the nutrients it
requires are supplied by the amniotic fluid 16-19. The innermost layer, nearest the
fetus, is the amniotic epithelium. Amniotic epithelial cells secrete collagen types
III and IV alongside non-collagenous glycoproteins (laminin, nidogen, and
fibronectin) that form the basement membrane, the next layer of the amnion16, 17,
18 . The compact layer of connective tissue adjacent to the basement membrane
forms the main fibrous skeleton of the amnion. The collagens of the compact
layer are secreted by mesenchymal cells in the fibroblast layer. Interstitial
xix
collagens (types I and III) predominate and form parallel bundles that maintain
the mechanical integrity of the amnion15-18. Collagen types V and VI form
filamentous connections between the interstitial collagens and the epithelial
basement membrane 17-20. There is no interposition of amorphous ground
substance between collagen fibrils in amniotic connective tissue at term, so the
amnion maintains its tensile strength throughout the late stages of normal
pregnancy. The fibroblast layer is the thickest of the amniotic layers, consisting
of mesenchymal cells and macrophages within an extracellular matrix16,17,18. The
collagens in this layer form a loose network with islands of noncollagenous
glycoproteins17- 20. The intermediate layer (spongy layer or zona spongiosa) lies
between the amnion and the chorion 17-20. Its abundant content of hydrated
proteoglycans and glycoproteins gives this layer its “spongy” appearance in
histologic preparations, and it contains a nonfibrillar meshwork of mostly type
III collagen18-20. The intermediate layer absorbs physical stresses by permitting
the amnion to slide on the underlying chorion, which is firmly adherent to the
maternal decidua18-20.
Although the chorion is thicker than the amnion, the amnion has greater tensile
strength. The chorion resembles a typical epithelial membrane, with its polarity
directed toward the maternal decidua18,19.
The fetal membranes retain amniotic fluid, secrete substances both into the
amniotic fluid and toward the uterus, and guard the fetus against infection
ascending the reproductive tract. The membranes normally rupture during
xx
labour. Premature rupture of the fetal membranes is defined as rupture of the
membranes before the onset of labour. Premature rupture of the membranes
occurring before 37 weeks’ gestation is usually referred to as preterm premature
rupture of the membranes.
Rupture of fetal membranes before the onset of labour creates a dilemma for the
practicing obstetrician, because once the membranes have broken the risk of
fetal or maternal infection, or both, increases. Preterm premature rupture of
membranes increases this management challenge, mainly because of the added
problem of prematurity.
2.2 PATHOPHYSIOLOGY OF PREMATURE RUPTURE OF
MEMBRANES
Evidence suggests that the mechanisms involved in the rupture of membranes
include biochemical, immunologic and bacteriologic events14-16, 21- 25. Currently,
it is widely accepted that term or preterm rupture is associated with structural
changes, caused by inflammatory processes induced by endocrine or infectious
triggers14-16,24,25. Considering the associated clinical risk factors of PROM,
researchers in this field have contributed to our understanding of the causes.
Various mechanisms have been proposed, including mechanical, as well as
infectious or inflammatory processes. It is apparent that a single
pathophysiologic mechanism is not responsible for all cases of premature
rupture of membranes, but rather a combination of processes is in operation14-17,
24, 25.
xxi
Early obstetricians attributed rupture of the membranes to physical stress
particularly that associated with labour, evidence from findings in research at
the cellular and molecular level however suggests that membrane rupture is also
related to biochemical processes, including disruption of collagen within the
extracellular matrix of the amnion and the chorion and programmed death of
cells in the fetal membranes9,24,25. It has been proposed that the fetal membranes
and the maternal uterine lining (decidua) respond to various stimuli, including
membrane stretching and infection of the reproductive tract, by producing
mediators, such as prostaglandins, cytokines, and protein hormones that govern
the activities of matrix-degrading enzymes24-27.
2.3 DIAGNOSIS OF PREMATURE RUPTURE OF MEMBRANES
Rupture of the membranes typically presents as a large gush of clear vaginal
fluid or as trickling fluid26,27. The differential diagnosis includes leakage of
urine or urinary incontinence, excessive vaginal discharge, such as physiologic
discharge or bacterial vaginosis and cervical mucus or show as a sign of
impending labour 26, 27.
Premature rupture of membranes is largely a clinical diagnosis8-12. It is
commonly suggested by a history of watery vaginal discharge and confirmed on
sterile speculum examination8-12, 28- 31. The traditional minimally invasive gold
standard for the diagnosis of rupture of membranes relies on the ability of the
clinician to demonstrate clinical signs of visual pooling of clear fluid in the
posterior fornix of the vagina or leakage of fluid from the cervical os during a
xxii
sterile speculum examination, an alkaline pH of the cervicovaginal discharge,
which is typically demonstrated by seeing whether the discharge turns yellow
nitrazine paper to blue, red litmus blue and or microscopic ferning of the
cervicovaginal discharge on drying8-12, 29 -32. Evidence of diminished amniotic
fluid volume by Leopold’s examination or ultrasound alone cannot confirm the
diagnosis, but may help to suggest it in the appropriate clinical setting.
Most of the commonly documented methods of diagnosing rupture of
membranes by identifying and utilising the distinguishing properties of the fluid
from the cervical os all have limitations in terms of diagnostic accuracy, cost,
and technical ease 7-10. Moreover, such tests become progressively less accurate
when more than 1 hour has elapsed after the membranes have ruptured. As
such, reliance on clinical assessment alone leads to both false-positive and false-
negative results7-10.
Nitrazine test is designed only to confirm an alkaline pH in the cervicovaginal
secretions the pH of the vaginal secretions is generally 4.5–6.0, whereas
amniotic fluid usually has a pH of 7.1–7.312, 21, 22. It is associated with high
false-positive rates related to cervicitis, vaginitis (bacterial vaginosis), and
contamination with blood, urine, semen, or antiseptic agents7-12, 21, 22.
The fern test refers to microscopic crystallization of amniotic fluid on drying,
and may give false-positive results due to fingerprints or contamination with
semen and cervical mucus as well as false-negative results due to technical error
using a dry swab to collect the sample or contamination with blood12,23.
xxiii
Reported sensitivity and specificity for the fern test are 51% and 70%,
respectively, in patients without labour and 98% and 88%, respectively, in
patients in labor 23,24.
Without clear evidence of amniotic fluid loss observed by speculum
examination, the diagnosis of premature rupture of membranes can be uncertain
and complementary diagnostic tests are frequently needed. The diagnostic
confirmation in ambiguous cases is a major challenge in current obstetric
practice, because correct diagnosis is necessary in order to decide upon the most
appropriate management and ultimately to reduce both maternal and foetal
complications. The optimal test should be specific for amniotic fluid and not be
affected by contamination from other corporal substances or vaginal
medications.
2.4 PLACENTAL ALPHA MICROGLOBULIN 1
Placental alpha microglobin1 was isolated in 1975 from amniotic fluid by D
Petrunin and was originally referred to as specific alpha 1 globulin of placenta.
Placenta alpha micoglobulin-1 is present in the blood, amniotic fluid and
cervico-vaginal discharge of pregnant women33. The concentration is several
thousand magnitudes higher than that which is found in vaginal discharge in
pregnant women when the fetal membrane is intact.PAMG-1 has been found to
be present in amniotic fluid throughout all three trimesters of pregnancy. The
concentration of PAMG-1 in cervical and vaginal secretions of pregnant women
without complications was measured and ranged from 0.05 to 0.22 ng/mL31-35
xxiv
PAMG-1 concentrations in the amniotic fluid fall into 2,000-25,000 ng/mL
range33,35. It has a concentration from 1,000- to 10,000-fold higher in amniotic
fluid than in the cervicovaginal secretion33,35. This sharp difference in the
measured range of placental alpha microglobulin 1 is considered an important
factor that can suggest presence of amniotic fluid and hence rupture of fetal
membranes35.
2.5 MANAGEMENT OF PREMATURE RUPTURE OF MEMBRANE
Premature rupture of membranes is an obstetric condition requiring prompt and
appropriate management to prevent morbidity and mortality of the fetus and
mother from resulting as consequence as a result of risk posed by the loss of the
protective function of an intact membrane. Management is largely dependent on
the gestational age, duration of rupture of membrane, presence of associated
complications like cord prolapse, chorioamnionitis and other considerations1-4.
Steroid administration is considered when foetal lung maturity cannot be
ascertained, appropriate broad spectrum antibiotics are administered when
infection is suspected or when duration of rupture of membranes is greater than
12 hours 1-4, 35-39. The decision to stimulate labour is taken when the gestational
age is at term and labour does not ensue in 12 hours. Patient could be managed
conservatively on steroids and antibiotics to allow for fetal lung maturity,
reduce the chances of intraventricular haemorrhage and necrotising enterocolitis
when clinical presentation is before term. Management of each case is
individualised based on the clinical presentation and the merit of the case1-4. The
xxv
management of the cases would be categorised for the purpose of this study into
three (i) conservative management which is applicable in cases of problems of
prematurity are envisaged, (ii) oxytocic stimulation when premature rupture of
membrane occurs at term, and (iii) allowing the process of labour continue in
cases where examination findings are in keeping with diagnosis of labour.
xxvi
CHAPTER THREE
3.1AIMS AND OBJECTIVES
1. To determine the sensitivity of placental alpha micro globulin 1(PAMG 1)
Amnisure ROM in diagnosing presence of amniotic fluid in cervicovaginal
secretions and hence diagnose rupture of fetal membranes
2. To compare Amnisure ROM with standard clinical assessment in diagnosing
rupture of fetal membranes.
3. To determine and compare the sensitivity and specificity of Amnisure ROM
and standard clinical assessment in diagnosis of premature rupture of
membranes.
3.2 HYPOTHESIS
Null hypothesis: There is no difference in the sensitivity and specificity of
Amnisure rom (PAMG1) and standard clinical assessment in the diagnosis of
premature rupture of fetal membrane.
Alternative hypothesis: The use of amnisure rom(PAMG1) is more sensitive
and specific than standard clinical assessment in diagnosis of premature rupture
of membranes
The findings from this study could either accept or reject the null
hypothesis.The p value is set at 0.05 at 95% confidence interval.
xxvii
CHAPTER FOUR
4.1 DESCRIPTION OF STUDY AREA
Ido Ekiti is one the towns in Ido Osi local government area of Ekiti State. Ekiti
state is one of the South-West states of Nigeria. It is situated entirely within the
tropics and is located between longitudes 40 51 and 50 451 East of the Greenwich
meridian and latitudes 70 151 and 80 51 north of the Equator. It lies south of
Kwara and Kogi states, East of Osun state and bounded by Ondo state in the
East and in the South. Ekiti state has three senatorial districts and sixteen local
government councils with a population of 2,384,212 people41.
4.2 STUDY LOCATION
This study was carried out in the Departments of Obstetrics and
Gynaecology of the Federal Teaching Hospital, Ido-Ekiti. This hospital serves
as a referral centre for primary and secondary health care centres in Ekiti state
and its environs.
4.3 STUDY POPULATION
Subjects for this study were from the population of pregnant women who
presented for delivery at the labour ward in the study locations and satisfied the
inclusion criteria.
4.4 STUDY DESIGN
The study was a prospective diagnostic study carried out at Federal Teaching
Hospital Ido Ekiti.
xxviii
4.4.1 SAMPLE SIZE DETERMINATION
The required sample size was determined using the Fisher’s statistical
formula.
𝑛 =[𝑧2𝑝(1−𝑝)]
𝑑2 42
Where
n= the desired sample size
z=1.96, which is the standard normal deviation at 95% confidence
interval (CI).
p= estimated prevalence of Premature rupture of membranes
q = 1- P
d= degree of accuracy desired, set at 0.05
From a previous study done in LAUTECH Osogbo South-West Nigeria,
the prevalence of premature rupture of membranes (P) is 3.9 %38.
Therefore, n = (1.96)² Х 0.039(1 - 0.039) = 57.59 (approx 58)
(0.05)²
With a deliberate oversampling of 10% to cater for non-responders, the
estimated sample size is 64.
4.4.2 STUDY PROCEDURE/ TECHNIQUE
All women with symptoms suggestive of PROM who presented at the facility
were recruited and further evaluated for rupture of membranes with a detailed
xxix
history, physical examination and a sterile speculum examination. All the
recruited patients had standard clinical assessment protocol for rupture of
membrane. The procedure of evaluation was carried out as follows by one of the
clinical assistants (all were post part 1 residents in the department of obstetrics
and gynaecology). The procedure was explained to the patient and a written
informed consent was obtained. The patient was thereafter placed in the dorsal
position and sterile speculum vaginal examination was performed. Standard
clinical assessment of leakage or egress of amniotic fluid from the cervical os
and or pooling of amniotic fluid was done by direct visualisation of the cervical
os during the procedure of sterile speculum examination of the patient and when
present were interpreted as positive for standard clinical assessment. The
findings during sterile speculum examination were recorded on the study
proforma. PAMG-1 immunoassay using the amnisure international kit
according to the manufacturer’s instructions39 was also done and the findings
recorded in the proforma. The kits used were obtained from Amnisure
International LLC 30 JFK Street, 4th Floor, Cambridge.
Using the amnisure kit involved the sterile polyethylene terephthalate swab
supplied by the manufacturer would be placed in the posterior fornix of the
vagina. After a period of 1 minute to ensure saturation, the swab was removed
and agitated in the provided solvent vial for 1 minute. The swab was discarded
and the amnisure test strip placed in the vial. The sample in the vial was allowed
to migrate through the test strip membranes by capillary action, and the test strip
xxx
indicated a negative or positive result after a maximum of 10 min. The test strip
was removed from the vial if two lines appear (indicating a positive result) or
after 10 minutes if only one line appeared (indicating a negative result). After an
initial assessment for rupture of membranes, all the women were managed
according to the departmental protocol. Management of patients recruited for
this study were based strictly on the findings of standard clinical assessment
during sterile speculum examination as it is the usual practice in Federal
Teaching Hospital Ido Ekiti. After an initial assessment for rupture of
membranes all women were managed by standard clinical algorithms. The final
evaluation (reference standard) was made by reviewing medical records after
delivery based on the presence of any of the following: membranes were overtly
ruptured at time of delivery (status of the membranes), positive pad chart with
presence of fluid that smells like amniotic fluid on the pad, delivery within 48 h
to 7 days (depending on gestational age), clinical evidence of chorioamnionitis,
and adverse perinatal/neonatal outcomes strongly correlated with prolonged
premature rupture of the membranes30. Management of patients were not
influenced or determined by the findings from the amnisure test, the amnisure
test result were blunted from the caregiver.
4.5.1 INCLUSION CRITERIA
All pregnant women who have passed the age of viability (28 weeks for
this study), presenting with history suggestive of premature rupture of
membranes and have given a written consent were recruited. Any parturient
xxxi
with any of the under-listed exclusion criteria will not be included. All neonates
born to recruited pregnant women will also be recruited into the study.
4.5.2 EXCLUSION CRITERIA
Patients to be excluded are those with active vaginal bleeding, those diagnosed
to have placenta praevia and those with intrauterine death.
4.6 DATA ANALYSIS
All the results were recorded in a proforma. Data analysis was done using
statistical program for social sciences (SPSS) version 18(SPSS Inc., Chicago,
Illinois, USA). Frequency tables were made and results tested for statistical
significance. Categorical data were compared using chi square(X2) test and
Fisher’s exact test where expected frequency is less than 5. The p value was
evaluated for statistical significance. A significant value is put at p < 0.05.
4.7 STUDY DURATION
This study lasted for a period of six months. The patients were adequately
counselled and their informed written consent obtained before they will be
recruited into the study.
4.8 ETHICAL CONSIDERATIONS
In designing this study, the following ethical issues were put into
consideration.
Informed consent to participate and withdrawal from study:
The purpose of the study was explained to the entire potential participants
both at the antenatal clinic and the obstetric emergency unit where patients
xxxii
present with history suggestive of premature rupture of membranes. The willing
patients signed informed consent forms. Participants were informed of their
freedom to withdraw or refuse to take part in the study without prejudice to their
usually expected standard of care.
Confidentiality of Data
All information including history, physical findings and results, obtained
from the participants were kept strictly confidential. The participants were
assured that their identity would be kept confidential by the investigator.
Beneficence to Participants
No patient participating in this study was made to pay for the tests. The
results obtained from the study would help in formulation of evidence-based
policy for care of women booking for antenatal care and their newborn. Patients
who tested positive were managed according to standard protocol in
management of premature rupture of membranes depending on the gestational
age and possible duration of rupture of membranes from history.
Non -Maleficence to the Participants
All precautions were taken to reduce the adverse effects that may be
inflicted by the study.
Justice
Method of patient selection was scientifically objective and ensured
fairness as explained in 4.5.1 above.
xxxiii
Ethical Clearance
Ethical Clearance for this study was obtained from the ethical review
board of the hospital where the study was undertaken, and a copy of the
clearance is being submitted with the dissertation.
Cost Implications
All costs were borne by the principal investigator. No cost was borne by
the patients.
xxxiv
CHAPTER 5
RESULTS
A total of sixty four (64) patients who fulfilled the inclusion criteria were
recruited for the study. All the patients went through the standard clinical
assessment for premature rupture of membrane according the protocol at
Federal Teaching Hospital Ido Ekiti. They were also assessed for the presence
or absence of placenta alpha microglobin 1 using the amnisure test strip.
Table 1 shows the socio-demographic characteristics of patients recruited for
the study. The mean age of patients who participated in the study was 29.6 ±
3.4years. Age bracket 30-34 years accounted for about 42.2% and was closely
followed by the 25-29 years age bracket which accounted for 40.6%, about
7.8% were over 35years of age. 35.9% of the participants were skilled workers,
9.4% were housewives while 12.5% were unemployed despite some level of
education. The religious distribution of the patients showed that a majority of
the patients (73.4%) were Christians while 26.6% practiced Islam. Most of the
patients had tertiary level of education, 45.3% were graduates of polytechnics
and universities while about 21.9% had national certificate of education. About
93.8% of the patients were married, while 6.2% cohabited.
xxxv
Table 1: The demographic characteristics of the patients at presentation
VARIABLES FREQUENCY
(%)
Age (years)
20 – 24 6 (9.4)
25 – 29 26 (40.6)
30 – 34 27 (42.2)
≥ 35 5 (7.8)
Mean ± SD 29.6 ± 3.4
Median (Range) 29.5 (23.0 – 37.0)
Occupation
Housewife 6 (9.4)
Unskilled worker 14 (21.9)
Semi – Skilled worker 5 (7.8)
Skilled Worker 23 (35.9)
Professional 8 (12.5)
Unemployed 8 (12.5)
Religion
Christianity 47 (73.4)
Islam 17 (26.6)
Educational Status
Primary/Arabic 4 (6.3)
Secondary 17 (26.6)
Teacher Training College 14 (21.9)
Polytechnic/ University 29 (45.3)
Marital Status
Co – Habiting 4 (6.2)
Married 60 (93.8)
xxxvi
Table 2 shows the clinical data of participants on admission. The gravidity of
patients ranged 1-8, while the mean of gravidity was 3.0 ± 1.4. The parity of
patients ranged from0-5, with a mean parity of 1.3 ± 1.3. The number of
children alive par participant ranged from 0-4, while the mean number of
children alive 2 ± 1.0. The estimated gestational age at presentation in weeks
ranged from 28.7 – 41.9 weeks while the mean age at presentation was 37.2 ±
2.4 weeks. About 65.6% of the patients evaluated presented at term while
34.4% were preterm.
The duration of symptoms in hours at presentation ranged from 2.0 –384.0
hours, the mean duration of symptoms was 20.3 ± 53.0hours.
About 57.8% of the patients presented with complaints of trickling of fluid par
vagina while 42.2% presented with a gush of fluid par vagina. In a majority
(84.4%) of the patients, the fluid at presentation was colourless, 10.9% were
yellowish while 4.7% were whitish.
Egress of fluid from the cervix was confirmed during sterile speculum
examination in forty-six (71.9%) of the patients, while there was no
demonstrable egress of fluid from the cervix in 18 (28.1%) of patients. Fifty-
two (81.2%) patients had at least a minimal pool of fluid in the posterior fornix
while there was no demonstrable pool of fluid in the posterior fornix of 12
patients (18.8%).
The amniotic fluid index of patients on ultrasound ranged from 4-14.1 while the
mean value of amniotic fluid index was 9.5 ± 2.1.
xxxvii
Table 2: The clinical data of participants on admission
N – 64
VARIABLE FREQUENCY (%)
Gravidity
Primigravidae 6 (9.4)
Multigravidae 58 (90.6)
Mean ± SD 3.0 ± 1.4
Median (Range) 3.0 (1.0 – 8.0)
Parity
Mean ± SD 1.3 ± 1.3
Median (Range 1.0 (0.0 – 5.0)
No of Children Alive
Mean ± SD 1.2 ± 1.0
Median (Range) 1.0 (0.0 – 4.0)
Estimated Gestational Age at Presentation (weeks)
25 – 33 weeks 4 (6.3)
34 – 36 weeks 18 (28.1)
>- 37 weeks 42 (65.6)
Mean ± SD 37.2 ± 2.4
Median (Range) 37.3 (28.7 – 41.9)
Duration of Symptoms (Hours)
Mean ± SD 20.3 ± 53.0
Median (Range) 5.5 (2.0 – 384.0)
History of Draining
Trickling par vaginam 37 (57.8)
Gush of fluid Par Vaginam 27 (42.2)
Colour of fluid
Colourless 54 (84.4)
Whitish 3 (4.7)
Yellowish 7 (10.9)
Egress from the cervix on sterile speculum exam
Yes
No
Pooling in the posterior fornix
46(71.9)
18(28.1)
Yes 52 (81.2)
No 12 (18.8)
Ultrasound Findings
Oligohydramnios 10 (15.6)
Normohydramnios 54 (84.4)
Ultrasound Amniotic fluid Index
Mean ± SD 9.5 ± 2.1
Median (Range) 9.6 (4.0 – 14.1)
xxxviii
Table 3 shows the result of findings following the standard clinical assessment
and the amnisure test. 52(81.2%) out of the 64 patients recruited had positive
amnisure tests while 46(71.9%) out the 64 recruited had positive results
following standard clinical assessment. Amnisure test had a sensitivity of
96.3% while the standard clinical assessment had a sensitivity of 84.3%.
The specificity as well as positive predictive values of both the Amnisure test
and standard clinical assessment were 100%. The negative predictive value was
however 83.3% for the Amnisure test and 55.6% for the Standard Clinical
Assessment.
xxxix
Table 3: Result of Amnisure test and Standard Clinical Assessment
Variable Amnisure
Test
95% C.I.
Standard
Clinical
Assessment
95% C.I.
Positive 52 46
Negative 12 18
Sensitivity (%) 96.30 87.25 – 99.55 85.19 72.88 – 93.38
Specificity (%) 100.00 69.15 – 100.00 100.00 69.15 – 100.00
Positive Predictive Value (%) 100.00 93.15 – 100.00 100.00 92.29 – 100.00
Negative Predictive Value (%) 83.33 51.59 – 97.91 55.56 30.76 – 78.47
xl
Table 4 compares the result of standard clinical assessment with Amnisure test
and shows that 45(70.3%) patients had positive test results in both the Amnisure
test and the standard clinical assessment while 11(17.2%) patients had negative
results for both tests. 7(10.9%) of the patients that had negative results
following standard clinical assessment had positive amnisure test results. Only
one patient (1.6%) that had a positive result following standard clinical
assessment was negative following the Amnisure test. Cumulatively, 52 patients
(81.2%) had a positive amnisure test result while 12 patients (18.8%) had
negative amnisure test results. Cummulatively, 46 patients (71.9%) had a
positive standard clinical assessment while 18 patients (28.1%) had negative
results following the standard clinical assessment, p value <0.001F and 0.035§
both of which imply a statistically significant difference between the amnisure
test and the standard clinical assessment.
xli
Table 4 : Comparing the result of standard clinical assessment with Amnisure test
Amnisure
Test
Standard Clinical
Assessment
Total
X2
p-value
Positive Negative
Positive 45 7 52 25.757 <0.001F
Negative 1 11 12
Total 46 18 64
0.035§
F = Fisher’s Exact Test § = McNemar Test
xlii
Table 5 shows the management decisions and outcomes following evaluation of
patients on account of premature rupture of membranes. Oxytocin stimulation
was commenced in 57.8%, about 17.2% progressed in labour spontaneously,
approximately15.6% of the patients were managed expectantly while 9.4% had
caesarean delivery for obstetric indications.
Fifty (78.1%) of the patients evaluated subsequently had term live births, while
14(21.9%) had preterm live births. Fifty one patients (79.7%) did not require
admission of their neonates after delivery, approximately 20.3% required
admission at the special care baby units.
xliii
Table 5 : The management and outcomes
VARIABLES FREQUENCY
(N = 64)
PERCENTAGE
(%)
Management Decision
Continue labour 11 17.2
Oxytocin stimulation 37 57.8
Expectant Management 10 15.6
Caesarean Delivery 6 9.4
Pregnancy Outcome
Preterm Live Birth 14 21.9
Term Live Birth 50 78.1
Neonatal Admission
Yes 13 20.3
No 51 79.7
Indications for admission were presumed sepsis and prematurity.
xliv
Figure 1: Showing summary of result for both standard diagnostic method and Amnisure
Initial Evaluatio
n
Rupture of Membranes by standard diagnosing method
N =46(71.9%)
Final Evaluation and Review
Confirmed rupture of membranes.
N = 54(84.4%)
No Rupture of Membranes. N = 10(15.6%)
Patients with symptoms of rupture of membranes. N = 64
N= 1
Rupture of membrane by Amnisure test. N = 52(81.2%)
Standard Test Positive Amnisure Test
Positive N = 45(70.3%)
Standard Test Positive
Amnisure Test Negative
N = 1(1.6%)
Standard Test Negative
Amnisure Test Positive
N = 7(10.9%)
Standard Test Negative
Amnisure Test Negative
N = 11(17.2%)
xlv
CHAPTER 6
DISCUSSION
This study compared the result of findings following evaluation of patients with
history suggestive of premature rupture of membrane using the usual clinical
assessment at Federal Teaching Hospital Ido Ekiti and the Amnisure test
(placenta alpha microglobulin 1assay). The demographic characteristics of
patients that were recruited were the same in both arms of the study since the
same set of patients were evaluated using both the standard clinical assessment
and Amnisure ROM.
Of the 64 patients that presented for evaluation, rupture of membranes was
detected in 46(71.9%) patients using the standard clinical assessment while the
Amnisure test strip detected rupture of membranes in 52(81.2%) patients. About
65.6% of the patients evaluated presented at term while 34.4% were preterm
unlike the study by Phupong et al44 in which seventy-six percent were preterm
and 24 % were at term.
According to the study by Lee SE et al12 in which 184 patients (11-42 weeks of
gestation) were evaluated, rupture of membranes was diagnosed at initial
presentation in 76% (139 of 184) using conventional clinical assessment and
85% (157 of 184) using placental alpha-microglobulin-1 immunoassay. Follow-
up confirmed that a total of 159 of 183 patients (87%) had rupture of
membranes at their initial presentations. The findings of Lee et al12 was similar
to this study in which about 72% of patients evaluated were diagnosed to have
xlvi
rupture of membranes at the initial evaluation using conventional clinical
assessment and 81% using placenta alpha-microglobulin 1 immunoassay at
initial presentation.
The sensitivity of the Amnisure strip was 96.3% against the 84.3% which was
observed following the usual clinical assessment at Federal Teaching Hospital
Ido Ekiti. The specificity and positive predictive value were both 100% for the
amnisure test and the standard clinical assessment. While the negative
predictive value was 83.3% and 55.6% respectively for the Amnisure test stip
and standard clinical assessment in this study. There was a statistically
significant difference in the diagnosis of PROM between the Amnisure study
and the standard clinical assessment, p value<0.001(Fishers exact) and 0.035
(McNemar).
The sensitivity and specificity of placenta alpha microglobulin 1 immunoassay
(Amnisure) in this study were similar to the findings reported by Cousins et al11
after evaluation of 203 symptomatic women with presenting complains
suggestive of rupture of membranes. According to Cousins et al11 the PAMG-1
test(Amnisure) had a sensitivity of 98.9%, specificity of 100%, positive
predictive value of 100% and negative predictive value of 99.1%, while Lee et
al12 following evaluation of 184 patients reported a sensitivity of 98.7%,
specificity of 87.5%, positive predictive value of 98.1% and negative predictive
value of 91.3%.
xlvii
According to Lee et al12 using longitudinal assessment as the clinical gold
standard, placental alpha-microglobulin-1 immunoassay confirmed rupture of
membranes at initial presentation with a sensitivity of 98.7% (157 of 159),
specificity of 87.5% (21 of 24), positive predictive value of 98.1% (157 of 160),
and negative predictive value of 91.3% (21 of 23). Lee SE et al12 concluded that
placental alpha-microglobulin-1 immunoassay was better than both the
conventional clinical assessment and the nitrazine test alone in confirming the
diagnosis of rupture of membranes.
In a prospective observational study, Phupong et al44 compared the efficacy of
PAMG-1 rapid immunoassay with conventional standard methods for the
diagnosis of rupture of membranes. Patients with symptoms or signs of
premature rupture of membranes were included in this study. Conventional
standard methods were performed to establish the diagnosis and were compared
with PAMG-1 immunoassay results. Rupture of membrane was diagnosed if
visualization of fluid leaking from the cervical os or 2 of the following 3
conditions were present: positive nitrazine test, ferning test, and nile blue test.
The diagnosis of rupture of membranes was confirmed by reviewing the
medical records after delivery. A total of 100 patients (gestational age 36.5 +/-
3.5 weeks, range of 22 to 41weeks of gestation) were recruited into the study.
Seventy-six percent were preterm and 24 % were at term. PAMG-1
immunoassay had a sensitivity of 97.2 %, specificity of 69 %, PPV of 90.8 %,
NPV of 90.9 % and an accuracy of 89 %. In contrast, conventional combined
xlviii
standard methods had a sensitivity of 88.7 %, specificity of 96.6 %, PPV of 98.4
%, NPV of 77.8 %, and accuracy of 91 % for the diagnosis of ROM. The
authors concluded that PAMG-1 immunoassay is a rapid method for the
diagnosis of ROM and it has a higher sensitivity than conventional standard
methods for the diagnosis of ROM.
In a prospective cohort study, Neil et al45 evaluated the clinical utility of
Amnisure. A total of 184 women presenting with a history of PROM to a
tertiary maternity hospital were included in this study. Before and after
Amnisure, the attending clinician assessed and recorded membrane status
(PROM or intact), his/her level of confidence in this diagnosis, and the intended
management plan. There was clinician uncertainty regarding the diagnosis of
PROM in 83 (47 %) women. Amnisure significantly increased clinician
confidence and led to a change of intended management in 23 (13 %) women.
In 33 women presenting with possible preterm PROM, 7 thought to have
PROM before Amnisure had a negative test, leading to a change of management
in these women. The authors concluded that Amnisure is clinically useful when
the clinician is uncertain about the diagnosis; but not useful when the clinician
is confident about the diagnosis.
In a comparative prospective study, Abdelazim et al31 examined the accuracy of
the PAMG-1 test (AmniSure) for the diagnosis of premature rupture of
membranes. A total of 150 pregnant women after 37 weeks gestation were
included in this study for induction of labour and divided into 2 groups
xlix
according to the presence or absence of premature rupture of membranes; 75
patients with premature rupture of membranes were included in group I and 75
patients without premature rupture of membranes were included in group II as
controls. Trans-abdominal ultrasound was done to detect the gestational age and
the amniotic fluid index (AFI less than or equal to 5 cm in PROM) followed by
sterile speculum examination to detect amniotic fluid pooling from the cervical
canal and for the collection of samples. The sensitivity and the specificity of
PAMG-1 to diagnose PROM were 97.33 % and 98.67 %, respectively,
compared with 84 % sensitivity and 78.67 % specificity for Ferning test and
86.67 % sensitivity and 81.33 % specificity for nitrazine test. The PPV and
NPV of PAMG-1 were 98.64 % and 97.37 %, respectively, compared with
79.74 % PPV and 83.1 % NPV for Ferning test and 82.28 % PPV and 85.91 %
NPV for nitrazine test. PAMG-1 was more accurate (98 %) for detection of
PROM than Ferning (81.33 %) or nitrazine (84.0 %) tests.
Birkenmaier et al33 evaluated the performance of the placenta alpha
microglobulin 1 immunoassay (AmniSure) in cervico-vaginal secretions in
patients with uncertain rupture of membranes and investigated the influence of
the examiners experience. This prospective cohort study was performed in
pregnant women (17 to 42 weeks of gestation) with signs of possible rupture of
membranes. Evaluation included clinical assessment, examination for cervical
leakage, nitrazine test as well as measurement of the amniotic fluid index by
ultrasound and Amnisure. Occurrence of rupture of membranes was based on
l
review of the medical records after delivery. A total of 199 women were
included in this study. Amnisure had a sensitivity of 94.4 %; specificity of 98.6
%; PPV of 96.2 %; NPV of 98.0 %. Clinical assessment showed a sensitivity of
72.2 %; specificity of 97.8 %; PPV of 92.9 %; NPV of 90.6 %. Amnisure was
more sensitive for diagnosing rupture of membranes (p value = 0.00596)
compared to clinical assessment, independent of the examiners experience.
Furthermore, the sole use of Amnisure reduced costs by 58.4 % compared to
clinical assessment. The authors concluded that Amnisure was more sensitive
compared to clinical assessment, independent of the examiners experience and
gestational age.
According to a study by Beng Kwang Ng et al46 where a total of 211 patients
were recruited. At initial presentation, 88.6% had ruptured membranes, while
11.4% had intact membranes. Placental alpha microglobulin-1 immunoassay
confirmed rupture of membranes at initial presentation with a sensitivity of
95.7%, specificity of 100%, positive predictive value of 100%, and negative
predictive value of 75.0%. By comparison, the conventional standard diagnostic
methods had a sensitivity of 78.1%, specificity of 100%, positive predictive
value of 100% and negative predictive value of 36.9% in diagnosing rupture of
membrane.
In tandem with other studies as discussed above, this study done at Federal
Teaching Hospital Ido Ekiti also identified that Amnisure is more sensitive than
li
clinical assessment in diagnosing premature rupture of membranes (χ2 = 25.757,
df = 1, p value < 0.001and by McNemar test, p value = 0.035). The amnisure
test also has a higher negative predictive value than the standard clinical
assessment in making a diagnosis of PROM (83.33% versus 55.56%).
Table 6 gives an at a glance overview of other studies involving amnisure in
making a diagnosis of premature rupture of membranes.
Table 6: Comparison of this study to other trials involving Amnisure
Study
Number
of
patients
Sensitivity
(%)
Specificity
(%)
Positive
predictive
value (%)
Negative
predictive
value (%)
FTH Ido Ekiti 64 96.3 100 100 83.3
Lee SE et al 184 98.7 87.5 98.1 91.3
Cousins et al 203 98.9 100 100 99.1
Eleje G et al 251 97.4 96.7 98.9 92.2
Phupong et al 100 97.2 69 90.8 90.9
Abdelazzim et al 150 97.3 98.7 98.6 97.4
Birkenmaier et al 199 94.4 98.6 96.2 98.0
Marcellain et al
Beng Ng et al
80
211
95
97.5
94.8
100
95
100
94.8
75
lii
CHAPTER 7
CONCLUSION AND RECOMMENDATION
7.1 CONCLUSION
This study concludes with the finding that Amnisure is more specific in the
diagnosis of ROM and therefore will contribute significant to the management
of women with rupture of membranes and avoid the possible complications that
could result by relying on visual inspection for the diagnosis of premature
rupture of membranes.The sensitivity and negative predictive value of the
Amnisure test was better than the standard clinical assessment in the diagnosis
of premature rupture of membranes. The accuracy and precision in diagnosis of
premature rupture of membranes can be increased and improved by placenta
alpha microglobulin 1 assay using the Amnisure test strip. It helps reduce the
clinical uncertainty.
7.2 RECOMMENDATIONS
1. More clinical studies are needed to evaluate the accuracy of Amnisure
test.
2. Make Amnisure test strip readily available at the gynaecological
emergency, antenatal clinics and labour ward.
3. Ensure that clinicians are familiar with the use of Amnisure test strip.
4. Complement clinical diagnosis of premature rupture of membranes with
the use Amnisure test strip to increase sensitivity and accuracy in
diagnosis.
liii
7.3 LIMITATIONS
1. Amnisure strip is not readily available
2. The cost of procurement of the Amnisure strip is huge
3. Financial constraint on my part.
4. Final confirmation of leaking liquor by gold standard injection of indigo
carmine was not possible due to its invasive nature.
WORK PLAN
S/N ACTIVITY TIME
1. Submit proposal to college and await
response
July 2015
2. Data collection November 2015 – April 2016
3. Data analysis and report writing Two weeks (1st and 2nd week;
May, 2016)
4. Vetting by supervisors One week 3rd week June,
2016)
5. Binding and submission of completed
dissertation to college
One week ( first week; July
2016)
liv
REFERENCES
1. ACOG Committee on Practice Bulletins-Obstetrics, authors. Clinical
management guidelines for obstetrician-gynecologists. (ACOG Practice
Bulletin No. 80: premature rupture of membranes). Obstet Gynecol. 2007;
109: 1007-1019.
2. Caughey AB, Robinson JN, Norwitz ER. Contemporary diagnosis and
management of preterm premature rupture of membranes. Rev Obstet
Gynecol. 2008; 1: 11-22.
3. Alexander J.M, Cox S.M. Clinical course of premature rupture of the
membranes. Semin. Perinat. 1996; 20: 369-374.
4. Odunsi A, Odutayo R. Premature rupture of fetal membranes. In: Okonofua
F, Odunsi K (eds). Contemporary Obstetrics and Gynaecology for
Developing Countries. Benin City: Women’s Health and Action Research
Centre. 2003; 430-453.
5. E Y Kwawukume. Premature rupture of membranes. In EY Kwawukume,
EE Emuveyan(eds). Comprehensive obstetrics in the tropics.2002; 151-156.
6. Duff P. Premature rupture of the membranes in term patients. Semin
Perinatol. 1996; 20: 401-408
7. Duff P. Premature rupture of membranes at term. N Eng. J Med. 1996; 334:
1053.
lv
8. Mercer BM, Goldenberg RL, Meis PJ, et al. The Preterm Prediction Study:
prediction of preterm premature rupture of membranes through clinical
findings and ancillary testing. Am J Obstet Gynecol. 2000; 183: 738-745.
9. El-Messidi A, Cameron A. Diagnosis of premature rupture of membranes:
inspiration from the past and insights for the future. J Obstet Gynaecol
Can. 2010; 32: 561-569
10. Yamada H, Fujimoto S. Rapid diagnosis of premature rupture of membranes
using a new kit employing anti-AFP monoclonal antibody. Arch Gynecol
Obstet 1995; 256: 57-61.
11. Cousins LM, Smok DP, Lovett SM, Poeltler DM. AmniSure placental alpha
microglobulin-1 rapid immunoassay versus standard diagnostic methods for
detection of rupture of membranes. Am J Perinatol 2005; 22: 317-320.
12. Lee SE, Park JS, Norwitz ER, Kim KW, Park HS, Jun JK . Measurement of
placenta alpha microglobulin-1 in cervicovaginal discharge to diagnose
rupture of membranes. Obstet Gynaecol 2007; 109 (3): 634-40.
13. Yild C, Tanir H, Sener T. Comparison of conventional methods (nitrazine
test, ferning test) and placental alphamicroglobulin-1 (PAMG-1) in
cervicovaginal discharge for the diagnosis of rupture of membranes. Int J
Gynaecol Obstet 2009; 107 (2): S530.
14. Di Renzo GC, Cabero L, et al."Guidelines for the management of
spontaneous preterm labour. J Matern Fetal Neonatal Med 2011; 24(5):
659-667.
lvi
15. Aplin JD, Campbell S, Allen TD. The extracellular matrix of human
amniotic epithelium: ultra-structure, composition and deposition. J Cell
Sci. 1985; 79: 119-213.
16. Moore RM, Mansour JM, Redline RW, Mercer BM, Moore JJ. The
Physiology of Fetal Membrane Rupture: Insight Gained from the
Determination of Physical Properties. Placenta. 2006; 27: 1037-1051.
17. Pan L, Shu J,Cai Z et al. The morphologic study of the characteristics of
neurobiology of the amniotic membrane. Clin J Rehabil Med. 2006; 21(1)
46-49.
18. Takashima S, Yasuo M, Sanzen N et al. Characteristics of laminin isoforms
in human amnion. Tissue cells. 2008; 40: 75-81.
19. Pasquinelli G, Tazzari P, Ricci F et al. Ultrastructural characteristics of
human mesenchymal stroma cells derived from bone marrow and term
placenta. Ultrastruc Pathol. 2007; 31(1): 23-31.
20. Al-Zaid NS, Bou-Resli MN, Ibrahim ME. Study of the connective tissue of
human fetal membranes. J Reprod Fertil. 1980; 59: 383-386.
21. Gray,Henry. Development of fetal membranes and placenta. Anatomy of the
human body, embryology. 20th edition. 1; 11: 1-22.
22. Erdemoglu E, Mungan T. Significance of detecting insulin-like growth
factor binding protein-1 in cervicovaginal secretions: comparison with
nitrazine test and amniotic fluid volume assessment. Acta Obstet Gynecol
Scand.2004; 83: 622-626.
lvii
23. Reece EA, Chervenak FA, Moya FR, Hobbins JC. Amniotic fluid
arborization: effect of blood, meconium, and pH alterations. Obstet
Gynecol. 1984; 64: 248-250.
24. Smith RP. A technique for the detection of rupture of the membranes: a
review and preliminary report. Obstet Gynecol. 1976; 48: 172-176
25. Rosemond RL, Lombardi SJ, Boehm FH. Ferning of amniotic fluid
contaminated with blood. Obstet Gynecol.1990; 75: 338-340.
26. Méhats C, Schmitz T, Marcellin L, Breuiller-Fouché M. Biochemistry of
fetal membranes rupture.Gynecol Obstet Fertil. 2011; 39: 365-369.
27. Elliot CL, Loudon JA, Brown N, Slater DM, Bennett PR, Sullivan MH. IL-
1beta and IL-8 in human fetal membranes: changes with gestational age,
labor, and culture conditions. Am J Reprod Immunol . 2001; 46: 260-267.
28. Marcellin L, Goffinet F. Are biological markers relevant for the diagnosis
and the prognosis of preterm premature rupture of membranes? Clin Chem
Lab Med. 2012; 14: 1015-1019.
29. Ramseur B, Vidaeff AC, Hoshi I, Park JS, Strauss A, Khodjaeva Z et al.
Diagnosis of rupture of membranes: a metanalysis. J perinal. Med. 2013;
41(3): 233-40
30. Eleje UG, Igwegbe OA, Ikechebelu IJ et al. Accuracy and cost analysis of
placenta alpha-microglobulin-1 test in the diagnosis of premature rupture of
fetal membranes in resources limited community settings. J Obstet
Gynaecol. Res. 2014; 41(1): 29-38.
lviii
31. Abdelazim IA, Makhlouf HH. Placntal alpha microglobulin-1 (Amnisure
test) for detection of premature rupture of fetal membranes, Arch Gynecol
Obstet 2012; 285: 985-989.
32. Davidson KM et al. Detection of premature rupture of membranes.
Rev.article. clin obstet gynecol 1991; 34: 715.
33. Birkenmaier A, Ries JJ, Kuhle J, et al. Placental alpha microglobulin -1 to
detect uncertain rupture of membrane in a European cohort of pregnancies.
Arch Gynecol Obstet 2012; 285: 21-25.
34. Petrunin DD, Griaznova IM, Petrunina IA,Tatarinov IS. Immunochemical
identification of organ specific human placental alphal-globulin and its
concentration in amniotic fluid. Akusherstvo i Ginekologiia. 1977; 1: 62–64.
35. Ananth CV, Oyelese Y, Srinivas N, Yeo L, Vintzileos AM. Preterm
premature rupture of membranes, intrauterine infection, and
oligohydramnios: risk factors for placental abruption. Obstet. Gynecol. 2004;
104: 71–77.
36. Cousins LM, Smok DP, Lovett SM, Poeltler DM, “AmniSure placental alpha
microglobulin-1 rapid immunoassay versus standard diagnostic methods for
detection of rupture of membranes. Am J Perinat. 2005; 22 (6): 317–320.
37. Omole-Ohonsi A, Ashimi A, Adeleke S. Spontaneous Pre-Labour Rupture
of Membranes at Term: Immediate versus Delayed Induction of Labour. W
Afr J Med. 2009; 28(3): 156–160.
lix
38. Adeniji OA, Atanda OOA, Interventions and neonatal outcomes in patients
with premature rupture of fetal membranes at and beyond 34 weeks gestation
at a tertiary heath facility in Nigeria. Br. J. Med. Medical Res. 2013; 3(4):
1388-1397.
39. Amnisure leaflet
40. Okeke TC, Enwereji JO, Okoro OS, Adiro CO, Ezugwu EC. The incidence
and management outcome of preterm premature rupture of membranes in a
tertiary hospital in Nigeria. Am J of Clin Med Res 2.1 (2014): 14-17.
41. The official website of Ekiti State, Nigeria… The Land of Honour available
at http://ekitistate.gov.ng/about-ekiti/overview/copy. Accessed on 18/02/15
42. Fisher A.A, Laing J.E, Stoeckel J.E, Townsend J.W. Handbook for family
planning operations research design. Population Council.1998.
43. Marcellin L, Anselem O, Guibourdenche J, et al. Comparison of two
bedside tests performed on cervicovaginal fluid to diagnose premature
rupture of membranes. J Gynecol Obstet Biol Reprod (Paris). 2011;
40(7):651-656.
44. Phupong V, Sonthirathi V. Placental alpha-microglobulin-1 rapid
immunoassay for detection of premature rupture of membranes. J Obstet
Gynaecol Res. 2012; 38(1): 226-230.
45. Neil PR, Wallace EM. Is Amnisure® useful in the management of women
with prelabour rupture of the membranes? Aust N Z J Obstet Gynaecol.
2010; 50(6): 534-538.
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46. Ng BK, Lim PS, Shafiee MN, et al., “Comparison between Amnisure
Placental Alpha Microglobulin-1 Rapid Immunoassay and Standard
Diagnostic Methods for Detection of Rupture of Membranes, BioMed
Research International. 2013, Article ID 587438. doi:10.1155/2013/587438
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APPENDIX I
PROFORMA (DATA COLLECTION FORM)
A COMPARISON BETWEEN AMNISURE PLACENTA ALPHA
MICROGLOBULIN-1 RAPIDIMMUNOASSAY AND STANDARD CLINICAL
DIAGNOSTIC METHOD FOR DETECTION OF RUPTURE OF MEMBRANES
IN FTH IDO EKITI.
1. Serial No Hospital Number:……………….
2. Age (Last birthday)
3. Occupation
1. House wife
2. Unskilled worker
3. Semi skilled worker
4. Skilled worker
5. Professional
4. Religion
1. Christianity
2. Islam
3. Others
5. Educational Status
1. None
2. Primary/Arabic
3. Secondary
4. Teacher Training College
5. Polytechnic/University
6. Marital Status
1. Single
2. Cohabiting
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3. Married
4. Separated
5. Divorced
6. Widowed
7. Parity_______________________________
8. Previous abortions
(a)Number of voluntary terminations of pregnancy_________
(b)Number of spontaneous terminations of pregnancy_______
9. Gestational age at presentation (in weeks)
(a) L.M.P.______________________________________
(b) E.D.D.______________________________________
(c)Gestational age (using earliest USS)____________________
9. Presenting symptoms
(a) Trickling of fluid par vagina
(b) Gush of fluid par vagina
(c) Others, specify_______________________________________
10.Duration of symptoms (in hours) as at presentation
_________________________________________
11. Colour of fluid seen par vagina
(a) Colourless
(b) Whitish
(c) Yellowish
(d) Greenish
Others specify__________________
12. History of vaginal examination before presentation at FTH Ido Ekiti
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(a) Yes (b) No
13. Ultrasound findings
(i)Amniotic fluid index__________________________________
( ii) (a)Anhydramnious
(b)Oligohydramnious
(c) Normohydramnious
14. Findings on sterile speculum examination
(a) Egress of fluid from the cervical os. (i) Yes (ii) No
(b)Pooling in the posterior fornix. (i)Yes (ii) No
(c) Others(specify) __________________________________________
15. Findings on using Amnisure pad
(a) Positive
(b) Negative
16. Latency interval______________________________
17. Management decision
(a) Continue labour
(b) Oxytocic stimulation
(c)Expectant management
18. Outcome of pregnancy
(a)Preterm live birth
(b)Term live birth
(c)Fresh still birth
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19. Neonatal admission
(a)Yes
(b)No
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APPENDIX II
CONSENT FORM
I,…………………………………………………………………………………
……… have been fully informed about the protocol for the study titled A
COMPARISON OF AMNISURE PAMG-1 and STANDARD CLINICAL
METHOD IN SUSPECTED RUPTURE OF MEMBRANES IN FMC IDO
EKITI.
I understand the study is towards comparing the effectiveness of amnisure
PAMG-1 and standard clinical diagnostic method in cases of suspected
premature rupture of membranes in a bid to better diagnosis and patient
management.
I have also been informed that agent for the study (amnisure pad) does not have
any adverse effect on patients and that the result will not affect my management
adversely.
That I will suffer no consequence if I refuse to volunteer for this study and that I
retain the right to decline further participation at any stage of the study.
I hereby voluntarily consent to be a participant in this study.
Patient’s Signature:________________________________
Date:____________________________________________
Witness:__________________________________________
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INFORMATION FOR PARTICIPANTS ABOUT THE STUDY AND
JUSTIFICATION.
The fetal membranes and liquor serve a number of important functions, one of
which is to act as a protective barrier to the fetus and maternal uterine cavity
from microorganisms, other functions include nutrition, supportive functions in
development, maintenance of appropriate intrauterine temperature among other
functions. Some or all of these functions are lost or become compromised when
there is a premature rupture of membrane.
The quest for accuracy in diagnosing premature rupture of membranes in order
to facilitate subsequent appropriate management is an on-going process. A lot
has been done in this regard but considering the grave consequence of the
inappropriately diagnosed cases, the benefits of increased accuracy in diagnosis
and management is worth investing. The cost of a wrong diagnosis and
inappropriate management of premature rupture of membranes cannot be
overemphasised because of the magnitude of effect on morbidity and mortality
of the newborn from prematurity, infections with the attendant complications
and possibility of jeopardy to the future reproductive capability of the woman
from ascending infections. Diagnosis of ruptured fetal membranes is of crucial
importance at any period in a pregnancy for prompt hospitalization and for
timely and proper treatment. The diagnosis of PROM is especially challenging
in equivocal cases with no pooling of fluid observed in the posterior fornix at
the speculum examination.
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