Reduced Placental Villous Tree Elaboration in Small-for-gestational-age Pregnancies: Relationship with Umbilical Artery Doppler Waveforms

Objective: Our purpose was to investigate the three-dimensional architecture of placental villi from normal and growth-restricted fetuses and relate findings to umbilical artery blood flow velocity waveforms.

Study Design: Placentas from term (n = 15) and preterm (n = 5) appropriately grown and term (n = 9) and preterm (n = 7) growth-restricted fetuses (birth weight < 10th percentile) were examined to determine the number of arteries per stem villus and the three-dimensional configuration of the villous trees and their vessels. Umbilical blood flow before delivery was assessed by Doppler ultrasonography. The effects of age and growth restriction were determined by two-way analyses of variance.

Results: Growth restriction was associated with reduced large vessel wall thickness (p < or = 0.05) but no reduction in the number of these vessels per stem villus. The volumes and surface areas of intermediate and terminal villi were reduced (p < or = 0.001), especially in preterm growth-restricted cases, where a marked reduction in diastolic blood flow velocity was observed in the umbilical artery.

Conclusions: Reduced villous development may contribute to abnormal umbilical artery blood flood flow, as assessed by Doppler ultrasonography, in some cases of intrauterine growth restriction.