ABO incompatibility in Chinese newborn infants

In this prospective study of 889 consecutive newborn infants born at the Taipei Municipal Jen-Ai Hospital, ABO incompatibility involving those blood type A or B infants whose mothers were type O (A-O or B-O) was found to be 15 per cent. The severity of hyperbilirubinemia was significantly exaggerated in 103 ABO incompatible infants when compared with 30 controls of O-O pregnancies. There was no significant difference in clinical severity between A-0 incompatibility and B-0 incompatibility, or between first-born and others. Cord bilirubin levels, early reticulocyte counts and early hemoglobin concentrations of 17 severe hyperbilirubinemic infants whose maximum serum bilirubin levels exceeded 15 mg/100 ml were significantly different from those of other ABO incompatible infants and the controls. There was no significant difference in early leukocyte counts and early platelet counts among ABO incompatible infants and controls. Screening direct Coombs test of cord blood was positive in 2 out of 101 studies. It is suggested that ABO incompatible infants with cord bilirubin level greater than 2.5 mg/100 ml represent a risk of subsequent hyperbilirubinemia. Phototherapy is an effective means of treating neonatal hyperbilirubinemia due to ABO incompatibility.