PLACENTA MORPHOLOGY AND ABSENT OR REVERSED END-DIASTOLIC FLOW VELOCITIES IN THE UMBILICAL ARTERY - A CLINICAL AND MORPHOMETRICAL STUDY

The aim of the study was to investigate if a relation exists between a bsent or reversed end diastolic (ARED) flow in the umbilical artery an d morphometric characteristics of the placenta. Geometric parameters w ere measured in the terminal villi of nine placentae, collected after a pregnancy complicated by ARED flow. Placentae from pregnancies with normal Doppler velocimetry in the umbilical artery were matched for ge stational age and formed the control group. Mean placental weight in t he ARED group was significantly lower than in the control group. Morph ometric characteristics of the terminal placental villi did not differ substantially between the two groups before 30 weeks gestation. After 30 weeks mean villous profile cross sectional area and diameter were significantly smaller in the ARED group than in the control group. The mean profile cross sectional villous diameter in the ARED group did n ot differ substantially before and after 30 weeks of gestation (2287 m u m(2) and 2303 mu m(2), respectively). Accelerated maturation of term inal villi occurs in placentae delivered after a pregnancy with ARED f low in the umbilical artery. Morphometric characteristics are signific antly different between placentae expelled after ARED velocities or af ter normal Doppler recordings in the umbilical artery. In ARED placent ae, a significantly more uniform pattern of small villi is found compa red with control placentae. (C) 1996 W. B. Saunders Company Ltd