Much has been written during the past decade concerning hemolytic disease of the newborn due to incompatibility between the Rh blood groups of the mother and her fetus. Criteria for the diagnosis of this type of erythroblastosis have been well established. More recently attention has focused on hemolytic disease due to incompatibility between the blood of the mother and her infant with regard to their ABO blood groups and the associated antibodies. In approximately 20% to 25% of pregnancies the ABO group of the mother and her fetus will differ. The majority of infants appear to be protected from harmful effects of this type of incompatibility. When AB hemolytic disease does occur, it is usually mild, and the majority of infants recover without transfusion. The severely jaundiced baby is in potential danger, however, and kernicterus may result.
Hemolytic disease due to anti-A and anti-B poses many problems in diagnosis. At