Low target birth weight or growth retardation? Umbilical Doppler flow velocity waveforms and histometric analysis of fetoplacental vascular tree.

Abstract

The placental vascular architecture of small-for-gestational-age fetuses seems to have an impact on the flow patterns in the umbilical arteries. Blood flow velocity waveforms of the umbilical arteries were measured by Doppler ultrasonography in nine small-for-gestational-age fetuses with elevated systolic/diastolic ratios of the umbilical arteries, seven small-for-gestational-age fetuses with normal flow patterns, and 14 appropriate-for-gestational-age fetuses with normal flow patterns. After delivery histomorphometric placental investigations were performed. Reduced end-diastolic flow velocities were significantly associated with both a reduction of vascularization within the terminal villi and adverse diffusion conditions, indicating insufficient functional maturity. The perfusion and diffusion capacity of small-for-gestational-age placentas with normal umbilical artery flow velocity waveforms was similar or even slightly better compared with the appropriate-for-gestational-age control values. These data suggest that Doppler flow velocimetry in the umbilical arteries is predictive of a vascular lesion within the placentas of small-for-gestational-age fetuses.