Early pregnancy ultrasonographic evaluation

1. Early Pregnancy Ultrasound
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2. OBJECTIVES
Ultrasonographic evaluation of early
pregnancy and its complications

3. Early Pregnancy Ultrasound report
NORMAL
ABNORMAL
 Location
 Structure
 Viability
 Dating
 Number
•Assessment of other pelvic masses ????
•Screening for fetal abnormalities ????
•Assisting CVS and amniocentesis????

4. Structure & Viability

5. Structures of 1st Trimester
Pregnancy
 Gestational sac
 Yolk sac
 Embryo/fetus
 Presence of cardiac activity

6. Gestational sac
Visible 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

7. 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

9. Confirming intrauterine
gestation

10. Confirming intrauterine gestation
1) Double decidual
sac sign
2) Intradecidual 3) Double bleb sign
sign

11. Dating

12. 12
10/28/14
Early ddaattiinngg ooff pprreeggnnaannccyy
 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

13. 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)

14. Diagnosis ooff mmuullttiippllee
pprreeggnnaannccyy

15. TTyyppeess ooff mmuullttiippllee pprreeggnnaannccyy

18. Twin peak (or Lambda sign) pathognomonic
for dichorionic placentation
T-sign pathognomonic
for monochorionic placentation

19. 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

20. Abnormal early (first
trimester) pregnancy

21. Abnormal early (first trimester)
pregnancy
 FFaaiilleedd eeaarrllyy pprreeggnnaannccyy..
 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)

22. FFaaiilleedd eeaarrllyy pprreeggnnaannccyy
&&
Pregnancy of uncertain viability

23. Failed early
pregnancy
(FEP(
Pregnancy of
uncertain viability
(PUV(
NNoo ccaarrddiiaacc aaccttiivviittyy
wwiitthh CCRRLL
≥≥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

24. 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

25. Anembryonic
Pregnancy

26. Pregnancy of unknown location

27. 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

29. Ectopic Pregnancy

32. True vs. pseudo-gestational sac

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

34. HETEROTOPIC PREGNANCY

35. Yolk
sac Fetal pole

36. Other types of ectopic pregnancy

37. Cer vical ectopic pregnancy
 GS within the cervix .
 Abnormally low sac position.
 Colour Doppler : hypervascular trophoblastic
ring in the cervical region .

38. 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 .

39. 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

40. Molar Pregnancy

41. Molar pregnancy
( Snow storm+ Theca-lutein cysts )

42. Subchorionic
Hemorrhage

43. Retained products of conception
(incomplete abortion)

44. 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%

45. 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

46. How to reduce biohazards
ALARA
As Low As Reasonably Achievable
ALARA principle:
 Lowest acoustic power
 Shortest duration
 Least exposure to sensitive target tissues

47. 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

48. 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.

49. E.mail:::ahwalid2004@yahoo.com