Changes in Umbilical-Cord Blood Oxygen Affinity after Intrauterine Transfusions for Erythroblastosis

Abstract

Abstract The oxygen affinity of umbilical-cord blood was measured in 15 infants who received intrauterine transfusions (IUT) of adult blood for severe erythroblastosis fetalis (EF), seven infants with EF and various degrees of anemia who did not receive IUT, and nine infants unaffected by EF. Adult erythrocytes retained their characteristic oxygen-binding properties after a prolonged residence: 56 ± 21 days (mean ±S.D.) in the fetus. Infants who received 2 to 4 IUT had a mean P50 (half-saturation oxygen tension at pH 7.40) of 27.1 mm of mercury. Erythroblastotic infants without IUT and normal infants had a P50 of 20.8 mm of mercury. A significant correlation was observed between the oxygen affinity of blood and the percentage of fetal hemoglobin. A negative regression of P50 on total hemoglobin concentration was seen in infants with IUT but not in the others. Infants who received IUT had increased concentrations of red-cell 2,3-diphosphoglycerate (2,3-DPG). Normal fetal growth and lack of acidosis at birt...