Umbilical venous volume flow and placental morphometry in cases of the syndrome of fetus retardation of growth

Abstract

Abstract: Objective to determine the reproducibility of measurement of umbilical venous volume flow components and to calculate umbilical venous volume flow in normal and of the syndrome of fetus retardation of growth (SFRG) in a cross-sectional study. Morphometric analysis was performed on placental samples from 58 pregnancies with abnormal Doppler waveforms in the uterine, placental and umbilical circulations at 32-34 weeks, and 10 pregnancies with normal waveforms. Results: The volume of placental villi reduced from 350.5 cm3 in controls to 286.4 cm3 (P < 0.05) in the severest cases. The volume of the fetal capillaries reduced from 59.7 cm3 to 20.5 cm3 (P < 0.05). These reductions were associated with increased placental infarction. The myometrial segments of the spiral arteries were severely constricted, demonstrating failure of physiological conversion secondary to deficient trophoblast invasion. Umbilical venous volume flow measurements demonstrate an acceptable reproducibility. Umbilical venous volume flow is reduced in the SFRG but, when related to fetal weight, both normal and reduced values were obtained. Conclusion: The placental vascular bed is greatly reduced in cases of chronic fetal hypoxia. We propose impaired placental perfusion causes oxidative stress and regression of the fetal vasculature, leading to fetal growth retardation. Measurements of umbilical venous vessel area and time-averaged velocity resulted in acceptable reproducibility of volume flow calculations, which show a seven-fold increase at 32-36 weeks of gestation. In SFRG volume flow is significantly reduced