MORPHOMETRIC STUDY OF THE PLACENTAL VESSELS AND ITS CORRELATION WITH UMBILICAL ARTERY DOPPLER FLOW

Objective: To determine the changes in the vessel-wall thickness and t he radius of the lumen in tertiary-stem villi of the placenta with adv ancing gestational duration and their relationship to umbilical artery Doppler flow studies. Methods: Placentas from 63 miscarriages and pre term and term deliveries (between 19 and 40 weeks) were used for morph ometric study of the tertiary-stem villi vessels. Each woman had under gone Doppler now study of the umbilical artery. The resistance index ( RI) was determined from the Doppler flow velocity waveform. Placental paraffin sections of 4-mu thickness were stained with hematoxylin and eosin and with periodic acid-Schiff reagents. The tertiary-stem villi and their vessels were examined microscopically and assessed morphomet rically using a personal computer with math co-processor and a touch-s ensitive screen overlying a video monitor. The monitor received micros copic images from a video camera that was mounted on a microscope. We determined vessel-wall thickness by tracing the outer and inner circum ferences of digitized vessel-wall images.Results: Wall thickness, but not lumen size, of the tertiary-stem villi vessels decreased significa ntly overall at a rate of 0.63 mu/week (P < .001). The rate of decreas e was 0.64 mu/week (P < .001) during the second trimester and 0.50 mu/ week (P < .001) during the third trimester. There was a significant co rrelation between the decrease in thickness and in RI (r = 0.83 [P < . 001], r = 0.78 [P < .001] in the second and third trimesters, respecti vely). Resistance indices were all within normal limits. Conclusion: P lacental tertiary-stem villi vessel-wall thickness decreases with adva ncing gestational age. There is a correlation between the changes in R I of the umbilical artery Doppler flow and the changes in mean wall th ickness of the placental vessels. Copyright (C) 1997 by The American C ollege of Obstetricians and Gynecologists.