A 28-year-old sensitized Rh-negative woman at 30 weeks gestation is being monitored after a previous affected pregnancy. Which fetal Doppler finding is the accepted non-invasive indicator of severe fetal anaemia that prompts consideration of intrauterine transfusion?
- A Middle cerebral artery peak systolic velocity above 1.5 multiples of the median for gestation ✓
- B Reversal of the ductus venosus a-wave
- C Umbilical artery pulsatility index above the 95th centile
- D Cerebroplacental ratio below 1.0
Correct answer: A. Middle cerebral artery peak systolic velocity above 1.5 multiples of the median for gestation
Explanation
In fetal anaemia the heart increases cardiac output and blood velocity rises, so the middle cerebral artery peak systolic velocity increases. A value above 1.5 multiples of the median detects moderate to severe anaemia and is the standard trigger for cordocentesis or intrauterine transfusion, largely replacing serial amniotic fluid delta OD450. The other options reflect placental insufficiency rather than anaemia specifically.
Reference: Williams Obstetrics, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.