Hemolytic disease of the newborn caused by anti-M antibody.

An unusual case of hemolytic disease of the newborn caused by anti-M antibody is presented. Hyperbilirubinemia was noted in a full-term baby boy at 4 days of age. A total of 160 mL of M-positive packed red blood cells from the baby's father were transfused during the next 9 days and the hemolytic process became aggravated. The baby was referred to our hospital at 14 days of age. Maternal anti-M was detected and the baby was transfused with 50 mL of M-negative packed red blood cells. The baby's condition stabilized and he was discharged uneventfully at 18 days of age.