Progress Toward Reversed Uterine Diastolic Flow in the Third Trimester - An Inauspicious Sign.

Background: Increased uteroplacental resistance is associated with high uterine artery pulsatility and resistance indices and early diastolic notching. Evolution toward reversed diastolic uterine flow in the third trimester was scarcely reported previously. The feature was related to severe complications for both mother and fetus.

Material and methods: Data were collected from 3638 pregnancies undergoing prenatal care in our hospital. In this study, we aimed to identify those pregnancies with development of a reversed diastolic flow at the spectral Doppler interrogation of uterine arteries later than 24 weeks of gestation. A secondary aim was to follow up and actively manage these pregnancies.

Results: Previously, reversed uterine diastolic flow was reported during the third trimester in four cases only. In our study three pregnancies only developed reversed uterine arteries diastolic flow, none being associated with preeclampsia. All cases evolved with complications at birth.

Conclusions: Progressive deterioration of uterine arteries flow is possible during pregnancy. Reversed diastolic flow is a rare occurrence in the third trimester of pregnancy. Based on current knowledge, it may be considered an ominous sign and should trigger a close follow-up. Future studies using routine investigation of uterine arteries flow late in pregnancy may prove informative.