Severe fetal hydrops resulting from ABO incompatibility.

Severe fetal hydrops was diagnosed at 34 weeks' gestation. Funipuncture revealed a normal 46,XX karyotype and a hematocrit of 20%. Cesarean delivery was performed. Neonatal blood testing showed blood type B positive, positive direct and indirect Coombs, and an anti-B antibody titer of 1:64. The maternal blood group was O positive with a titer of 1:65,536 immunoglobulin G (IgG) anti-B antibody (after inactivation of IgM anti-B antibody). This report documents a rare case of fetal hydrops resulting from ABO incompatibility with neonatal survival.