Fetal and uteroplacental flow velocity waveforms and placental grading.

Doppler studies were performed on umbilical, fetal internal carotid, and arcuate arteries within 36 to 40 weeks of gestation in 85 women (66 with healthy pregnancies and 18 complicated by growth retardation, and results were analyzed by calculating the pulsatility index. In each case the placenta was examined and graded sonographically. No significant correlation was found between pulsatility index in fetal and uteroplacental vessels and placental grading in normal pregnancies. This suggests that tissue changes responsible for the echogenicity of maturing placenta are not directly related to vascular impedance of the placental vascular bed.