[Flow in the umbilical cord in normal and high-risk pregnancies].

The author studied umbilical venous blood flow in 100 normal pregnant women and in 100 pregnant women with apparent delay in intrauterine growth (DIUG). At birth, it was shown that only 50 babies had DIUG and that the blood flow was low in 49. In the other 50 babies there was no DIUG and blood flow in the umbilical vein was normal in all of them. The same study was carried out in 50 pregnant women with fetal hypoxia due to placental pathology (32), hemorrhage in the third trimester (15) and Rh isoimmunization (3). This study showed that increased blood flow in the umbilical vein is an early and sure sign of hypoxia due to placental pathology, hemorrhage in the last three months of gestation or Rh isoimmunization. It was also ascertained that low umbilical venous blood flow is a bad prognostic sign because it indicates that the fetus receives an abnormally low quantity of originated blood from the placenta, as was the case of the fetus with DIUG or in the final stages of hypoxia, and that when this happens, the fetus is already incapable of controlling the compensatory circulatory mechanisms and is at imminent risk of cardiac damage.