ABO hemolytic disease: a comparative study of clinical severity and delayed anemia.

The hospital and clinic records of 230 neonates with ABO hemolytic disease (HD) were reviewed. There was no significant difference in clinical severity between AO-HD and BO-HD as measured by (1) number of neonates with hyperbilirubinemia and/or those requiring exchange transfusion; (2) hemoglobin concentration; (3) reticulocyte count; (4) bilirubin concentration; and (5) incidence of anemia after discharge from the hospital. There was no difference in the hemoglobin concentrations measured at between four and eight weeks of age in 39 control infants and infants with either AO-HD or BO-HD who did not require an exchange transfusion. Our data do not indicate a clinical difference in the severity of AO-HD and BO-HD. Infants with ABO-HD who do not require exchange transfusion and/or phototherapy and whose hemoglobin concentration at discharge is greater than 15 gm/dl do not need a hemoglobin measurement before 6 weeks of age.