Umbilical vein blood flow in the human fetus in cases of maternal and fetal anemia and uterine bleeding.

The umbilical vein blood flow (UVBF) of the human fetus was studied by a method combining real-time and Doppler equipment in seven cases of maternal anemia, 20 cases of Rh isoimmunization and 19 cases of uterine bleeding during the third trimester of pregnancy. The last individual UVBF value before delivery had in Rh-isoimmunization a significant negative correlation with the cord hemoglobin level of the newborn infant (p less than 0.01), thus reflecting the severity of fetal hemolytic anemia. Severe isoimmunization (cord hemoglobin less than or equal to 140 g/l) was associated with a significantly higher UVBF, blood velocity in the umbilical vein and umbilical vein diameter than was observed in mild-moderate anemia. Maternal anemia seems to be causally associated with increased UVBF levels. Uterine bleeding, especially before the 34th week, often leads to increased UVBF in the fetus. The method used seems not only to be able to contribute to our knowledge of hemodynamic regulation in the human fetus, but also provides a new practical means of evaluating the severity of fetal affection in cases of Rh isoimmunization.