Early Pregnancy Ultrasound

Presented byPresented by

Dr/ Ahmed Walid AnwarDr/ Ahmed Walid AnwarAssistant professor of Obs & Gyn Assistant professor of Obs & Gyn

Benha Faculty of MedicineBenha Faculty of Medicine

EgyptEgypt20142014

OBJECTIVES

Ultrasonographic evaluation of early

pregnancy and its complications

Early Pregnancy Ultrasound report

NORMAL

ABNORMAL

Location Structure Viability Dating Number

•Assessment of other pelvic masses ????

•Screening for fetal abnormalities ????

•Assisting CVS and amniocentesis????

Structure & Viability

Structures of 1st Trimester Pregnancy

Gestational sac

Yolk sac

Embryo/fetus

Presence of cardiac activity

Gestational sacVisible at 4-5wks GA with

TVUS & at 6 wks GA with TAUS.

Eccentric echogenic ring with anechoic center .

Measure by Mean Sac Diameter.

GS size increases by about 1mm/day in early pregnancy

Discriminatory zone: serum hCG level in which GS is expected to be visible by US : hCG >2000 mIU/ml by TVUS& hCG >6000 mIU/ml by TAUS

Structures of 1st Trimester Pregnancy

Yolk sac: : bright ring with anechoic center located inside GS

seen at 5wk GA & persists to 11-12 weeks. Embryo/fetus: seen by TVUS as thickening of yolk at 6wks GA.

Presence of cardiac activity: usually seen around the time fetal pole is present, further confirming viability (6th wks)

Yolk sac

Fetal pole

Confirming intrauterine gestation

Confirming intrauterine gestation

1) Double decidual sac sign

3) Double bleb sign2) Intradecidual sign

Dating

04/13/2312

Early dating of Early dating of pregnancypregnancy

5 – 9 weeks : use of mean GS diameter

6 – 12 weeks : use of CRL (most accurate

dating of early pregnancy)

After 12 weeks : use of BPD

5 – 9 weeks : use of mean GS diameter

6 – 12 weeks : use of CRL (most accurate

dating of early pregnancy)

After 12 weeks : use of BPD

Formulas to Calculate gestational age

MGSD (mm) + 30

= gestational age

(days) (between 5

and 9 weeks)

CRL (mm) + 42 =

gestational age

(days) (between 6

and 12weeks)

Diagnosis of multiple Diagnosis of multiple pregnancypregnancy

Types of multiple pregnancyTypes of multiple pregnancy

Twin peak (or Lambda sign) pathognomonic for dichorionic placentation

T-sign pathognomonic for monochorionic placentation

Other roles of US Confirm fetal number . Confirm viability. Diagnosis of vanishing twin syndrome. Exclude any malformation or conjoined twins

(especially at age > 35y = genetic amniocentesis)

Needed with other procedures CVS fetal reduction

Abnormal early (first trimester) pregnancy

Abnormal early (first trimester) pregnancy

Failed early pregnancy.Failed early pregnancy.

Pregnancy of uncertain viability (i.e. IU pregnancy in a situation with no

enough criteria (usually on ultrasound grounds) to confidently categorize a pregnancy

as a miscarriage).

Pregnancy of unknown location.

Ectopic pregnancy

Trophoblastic disease

Subchrionic hemorrhage

Incomplete abortion (retained products of conception)

Failed early pregnancyFailed early pregnancy

& &

Pregnancy of uncertain viability

Failed early pregnancy

(FEP(

Pregnancy of uncertain viability

(PUV(

No No cardiaccardiac activity activity with with CRLCRL

≥≥77mmmm < 6mm

No fetal pole with MSD

> 25 mm (Anembryonic

Pregnancy)

< 20mm

Others Absence or inadequate growth on serial scans at least 7-10 days

Mean GSD < 25mm and containing yolk sac only

Management Termination Follow up US in 7-14 days with serial beta HCG correlation…viable or nonviable.

TVUS criteria of :Doubilet et al., N Engl J Med. 2013 Oct 10;369(15):1443-51

US poor prognostic indicators of pregnancy include:

No yolk sac, where:MSD > 8 mm embryo seen

Irregular gestational sac Low position of the gestational sac

Doubilet et al., N Engl J Med. 2013 Oct 10;369(15):1443-51

Anembryonic Pregnancy

Pregnancy of unknown location

Pregnancy of unknown location (PUL)

PUL = +ve pregnancy test + no IU or Ext.U pregnancy in US scan

↓↓↓↓↓Differential diagnosis is:

1. very early pregnancy, not detected with ultrasound

2. complete miscarriage

3. unidentified ectopic pregnancy

Ectopic Pregnancy

True vs. pseudo-gestational sac

True GS (DDSS)

Fluid collection (or sac) shows a small “beak sign” that connects with or points toward the uterine cavity line

HETEROTOPIC PREGNANCY

Yolk sac Fetal pole

Other types of ectopic pregnancy

Cervical ectopic pregnancy

GS within the cervix . Abnormally low sac position. Colour Doppler : hypervascular trophoblastic

ring in the cervical region .

Interstitial ectopic pregnancy

Eccentric gestational sac: the diagnosis is suggested by

visualisation of an intrauterine gestational sac or

decidual reaction located high in the fundus, that is

surrounded by less than 5 mm of myometrium in all

planes.

Interstitial line sign : an echogenic line from the mass

to the endometrial echo .

Sonographic features of Caesarean scar ectopic pregnancy (CSEP)

empty uterus

empty cervical canal

GS in the anterior part of

the lower uterine segment

absence of myometrium

between the bladder wall

and the GS

Molar Pregnancy

Molar pregnancy ( Snow storm+ Theca-lutein cysts )

Subchorionic Hemorrhage

Retained products of conception (incomplete abortion)

Thickened Nuchal Tanslucency (NT): Used for screening (SS) for Down’s syndrome in first trimester

Serial screening: Pregnancy associated plasma protein levels, hCG levels, NT thickness

Measured during 11-14 wks gestational age Seen on sagittal image as increased subcutaneous non-septated fluid in posterior

fetal neck Measurement >3mm usually considered abnormal, however exact cut off

measurements are dependent on maternal age/gestational age Detection rate of screening for Down’s Syndrome in first trimester:

sequential screening with NT: 82-87% NT alone: 64-70%

Safety of ultrasound in pregnancy

General perception is that ultrasound is safe (It is not

ionising radiation)

However, bioeffects can be either thermal or mechanical

(i.e. cavitations) with high power ultrasound

One RCT of repeated routine ultrasound with Dopplers in

the 3rd trimester found a small but significant decrease in

birth weight in the exposed cohort

A meta analysis showed males exposed to ultrasound in

uterus are more likely to be left-handed

How to reduce biohazards

ALARAAs Low As Reasonably Achievable

ALARA principle: Lowest acoustic power Shortest duration Least exposure to sensitive target tissues

Take home message

Ultrasound is no substitute for a good history

ALWAYS do an abdominal scan with ( Full bladder)

before using the vaginal probe with ( Empty bladder)

You will always be better than sonographers because

you know the anatomy and pathology

Avoid premature conclusions

Take home message Systematic scan should be performed

US scans are useful to be combined with HCG tests

before decision.

With ultrasound , an early intervention or

conservative management in pregnancy can be

determined.

General perception is that ultrasound scan is safe in

pregnancy.

E.mail:::ahwalid2004@yahoo.com