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.