[Limits of routine blood group serology in perinatal diagnosis].

We report on a multigravida with high-titer Rh-incompatibility who was admitted for delivery at term. Multiple intrauterine transfusions had resulted in nearly total replacement of fetal cells with donor cells. Routine serologic methods were unable to determine the blood group of the newborn and resulted in a falsely negative direct antiglobulin test. Four weeks later the newborn developed severe anemia in need of transfusion. The anemia was explained by a) suppression of erythropoesis because of early optimization of tissue oxygenization with the prenatally transfused HbA-containing donor cells, b) their limited survival in the infant and c) the accelerated elimination of the baby's own red cells by the maternal antibody.