A woman with severe preeclampsia at 32 weeks is being managed expectantly. Her cervix is unfavorable. Uterine artery Doppler shows bilateral notching with PI >95th centile. Fetal growth is on the 8th centile. Which additional Doppler finding would be the strongest indication to deliver immediately regardless of gestational age?

• A Middle cerebral artery PI below the 5th centile
• B Umbilical artery S/D ratio >3
• C Umbilical artery end-diastolic flow reduced but present
• D Ductus venosus absent or reversed 'a' wave ✓

Explanation

Absent or reversed 'a' wave in the ductus venosus reflects severe right heart dysfunction and imminent fetal decompensation; it is the strongest Doppler signal mandating immediate delivery regardless of gestational age. Absent end-diastolic flow in the umbilical artery warrants intensive surveillance, but reversed ductus venosus flow represents the final stage before fetal demise. MCA PI below the 5th centile (brain-sparing) also warrants concern but is not the absolute delivery trigger that reversed ductus venosus 'a' wave is.

Reference: Williams Obstetrics, 26th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.