Hemolytic disease of the newborn due to anti S antibodies.

We report a case of hemolytic disease in a newborn due to anti S antibodies. Baby R was born at term to an O+ mother whose antibody screen was positive for phenotype big S. Cord blood eluate revealed anti-S RBC; antigen: RBC typing for S- was positive. Physical examination of baby was unremarkable. The infant's HCT was 44.2 at 6 hours of age. At 48 hours, the HCT decreased to 33.5, bilirubin peaked to 5.4, retic had peaked to 6.8. By seven days, all these values reverted to the normal, and baby has remained asymptomatic.