Glycosylated fetal hemoglobin. Correlation with hyperglycemia and birth weight in infants of diabetic mothers.

Glycosylated fetal hemoglobin levels were measured in umbilical cord blood of normal infants and infants of diabetic mothers. The glycosylated fraction proved to be a stable compound; its level remained unchanged over a 19-day period. Exposure of fetal and adult hemoglobins to the same concentrations of glucose in vitro resulted in similar levels of glycosylated hemoglobins, suggesting that both types of hemoglobin are about equally reactive with glucose. Levels of glycosylated hemoglobin were significantly increased above normal in umbilical cord blood of infants of both Class A and Class B diabetic mothers. A significant relationship was found between macrosomia, reflected in birth weight ratios, and glycosylated hemoglobin from fetal erythrocytes in infants of diabetic mothers. While these data are consistent with the conclusion that glycosylated fetal hemoglobin levels are a function of fetal blood glucose concentrations in utero during the 2 mo before delivery, it is not known whether the glycosylated hemoglobin contributes to the abnormalities other than macrosomia found in infants of diabetic mothers.