This document provides guidelines for managing fetuses that are small-for-gestational-age (SGA) and discusses the use of Doppler studies. It defines SGA and discusses risk factors. For high-risk pregnancies, low-dose aspirin is recommended to reduce preeclampsia risk. Uterine artery Doppler is recommended starting at 20-24 weeks for those with minor risk factors to detect placental insufficiency. Abnormal uterine artery Doppler warrants serial fetal growth ultrasound. Late-onset FGR may not be detected by uterine artery Doppler alone after 34 weeks. Ductus venosus and middle cerebral artery Doppler can help time delivery in growth-restricted fetuses.

1. Updates of the Management of
Small–for–Gestational–Age Fetus
& Doppler Studies
Dhammike Silva

3. objectives
 Definitions
 Risk factors at booking
 Uterine artery Doppler
 Umbilical artery Doppler
 Dutus venosus doppler
 MCA Doppler
 Concept of Cerebro-placental ratio
 Timing of delivery
 Practical demonstration

4. Definitions…
 SGA
 Estimated fetal weight (EFW) or abdominal circumference (AC)
less than the 10th centile
 Severe SGA < than 3rd centile.
 FGR is not synonymous to SGA
 pathological restriction of the genetic growth potential

5. Plotting on charts???
 Customized Vs Population charts
 Customized = adjusting for maternal height, weight, parity, ethnicity, and other
physiological variables.
 Better identification of SGA
 No randomized controlled trial evidence comparing population to customized

6. 2500 g

7. Serial Vs Single…
2500 g
Serial in
3/52 apart

8. Risk factors…
Major risk factor (OR > 2.0)
 Age > 40 yrs
 Previous SGA
 Previous Still births
 Maternal and paternal SGA
 Chronic HT, preeclampsia
 DM with vasculopathy
 Cocaine, heavy smoking
Should offer
serial ultrasound
measurement of
EFW & UA PI
since 26–28
weeks

9. ASPRE Trial…
“meta-analysis reported that the administration of low-
dose aspirin in high-risk pregnancies is associated with
a decrease in the rate of PE by approximately 10%
(Askie et al, 2007) “
NNT was 9 (95% CI 5.0–17.0)

10. Risk factors…
Minor risk factor (OR < 2.0)
 age > 35
 BMI <20 or > 30
 Hx of preeclampsia
 Placental abruption
If 3 or more-
Should offer Ut
Artery Doppler
at 20-24 weeks

11. Incresed resistant of
Ut artery
Due to multiple risk
factors for poor
placentation
Decresed diastolic
flow

12. Pulsatility index…
PI = Peak systolic velocity – Peak diastolic velocity
Mean velocity
Decreased diastolic flow Incresed PI

13. Uterine Artery Doppler…
 Why in minor risk factors only ???
 In high risk populations - moderate predictive value
 low risk populations, High LR+ than high risk populations
 abnormal result - Serial assessment of fetal size and umbilical
artery Doppler from 26–28 weeks
 normal result - may still be value in a single assessment of
fetal size and umbilical artery Doppler
Then WHY ???

14. Place for SFH…
Serial measurement with plotting
From 24 weeks onwards
Improves prediction of a SGA neonate
<10th centile or serial measurements of static growth
, crossing centiles - referrer for ultrasound

15. Uterine artery Doppler…
Foetus retain blood in
circulation
Poor placentation
and poor blood flow
to foetus
Increased resistance
of uterine artery
Decreased diastolic
flow

16. Pulsatility index…
PI = Peak systolic velocity – Peak diastolic velocity
Mean velocity
Decreased diastolic flow Incresed PI

17. UA Doppler…
 Normal flow indices  repeat every 14 days.
 More frequent Doppler if severely SGA fetus.
 Abnormal doppler flow indices (UA PI > +2 SDs above mean for
gestational age)
 delivery is not indicated
 End–diastolic velocities present  twice weekly
 Absent/reversed end–diastolic frequencies  daily

18. How to messure UA Doppler…
 Free loop
 Away from placenta and abdominal insertion
 Vessel 2-4 mm diameter
 Angle between vessel & US beam - 0 degree
 If twins closer to abdomen

19. Absent Vs Reversed…

20. Pathophysiology of pulsatile venous flow…
UA resistence futher
increase
foetal heart adapts to
increase pressure in
venous system
Pulsatility appears in
UV

21. Ductus venosus Doppler…
 This triphasic waveform
 S wave: fetal ventricular systolic contraction - highest peak
 D wave: fetal early ventricular diastole - second highest peak
 A wave (or rather trough): fetal atrial contraction - lowest point in the wave , still
being in the forward direction
S
D
A

22. DV Doppler, redused A wave and
appearing pulsatility…

23. Ductus venosus Doppler…
Absent or reversed Diastolic flow of UA doesn’t
mean need delivery
DV has moderate predictive value for acidaemia and
adverse outcome
used to time delivery

24. How to messure DV Doppler…
right ventral mid-sagittal view of the fetal trunk
color flow mapping
demonstrate the umbilical vein, ductus venosus and
fetal heart
insonationa angle should be 30°

25. Early Vs. Late FGR…
UA Doppler with timing of delivery with DV – if
diagnosed < 34 weeks
Why UA Doppler may fail to diagnose FGR after 34
weeks ???

26. Why UA Doppler may fail to diagnose FGR after
34 weeks ???
 UA Doppler normal in late FGR
 Even few hours before IUD
Why???
 Large placenta after 34
 >50% of placenta should be malfunction to UA Doppler to become abnormal
 Unlikely to occur

27. Middle Cerebral Artery Doppler…
Smart foetus increase blood
flow to Brain and adrenals
shutting down others
In normal state small
systolic flow enough to
maintain cerebral perfusion
Decrease resistance of
MCA
Increase Diastolic flow

28. Pulsatility index…
PI = Peak systolic velocity – Peak diastolic velocity
Mean velocity
Increased diastolic flow Decreased PI

29. Middle Cerebral Artery Doppler…

30. Cerebro-placental ratio…
CPR= MCA PI
UA PI
In late FGR MCA PI decreases – CPR also decrease

31. Plotting of MCA PI or CPR

32. Timing of Delivery…
Early FGR with Umbilical artery AREDV prior to 32 weeks
 Abnormal DV Doppler
 Appearance of UV pulsations
 Provided fetus viable and completed steroids
Place fpr computerized CTG Interpretation - based on short term fetal heart rate variation
(CTG STV )
 Fetal heart rate (FHR) variation is the most useful predictor of fetal wellbeing in SGA
fetuses
Late FGR
 If MCA Doppler or CPR is abnormal, delivery should be recommended no later than 37
weeks.

33. Trial Randomizing Umbilical & Foatal FLow in
Europe…
TRUFFLE Study 2015
 Compare Early ductus changes, late ductus changes and computarized
CTG guided delivery Vs. 2 year neurodevelopment outcome of babies
“ deferring delivery until the DV a wave has disappeared ( until delivery is
mandated earlier by the CTG safety net criteria) compared to delivery based
only on CTG STV changes possibly results in a small excess of antenatal
deaths, but also in significantly improved survival without impairment at 2 years
age corrected for prematurity “

34. Audit of adherence…
 Risk assessment at booking
Take histories,may ask, but no major vs. minor risk classification and planning Doppler
studies
 20-24 wk – Ut Artery Doppler in minor risk
 Serial USS and plotting in charts of EFW and AC
 Plotting UA Doppler in population charts
 If AREDF using DV Doppler studies to time delivery
 Using MCA PI and CPR in late FGR with plotting for timing

35. Thank you…