Fetal intraperitoneal injection of immunoglobulin diminishes alloimmune hemolysis.

We report a case of severe fetal anemia associated with maternal anti-M antibody that was treated by direct injection of pooled human immunoglobulin into the fetal abdominal cavity. Four treatments at a dosage of 2 g per-kg estimated fetal body weight were performed, and no side effects were observed. A healthy baby girl was delivered transvaginally at 38 weeks, with neither exchange transfusion nor phototherapy required. Follow-up over 12 months found no indications of anemia or developmental delay in the child. This is believed to be the first report of fetal anemia in a blood-type-incompatible pregnancy being treated successfully with only direct immunoglobulin injection into the fetus. The immunoglobulin may have functioned as a neutralizing antibody causing the anemia to improve.