Reversed diastolic flow in the uterine artery - a new Doppler finding related to placental insufficiency?

Increased uterine artery pulsatility and resistance indices with or without notching of the waveform have been associated with an increased risk of pre-eclampsia and fetal growth restriction. However, reversed diastolic flow in the uterine artery has not previously been reported. We present two high-risk obstetric cases complicated by severe placental insufficiency: pre-eclampsia followed by eclampsia in one case and intrauterine growth restriction with abnormal cardiotocography in the other. Doppler studies of the uterine arteries revealed reversed diastolic flow in both cases. The pathophysiology and potential implications are discussed.