Prevention of Rh immunization after massive Rh-positive transfusion.

Case l.3.Mrs. P. is group AB, Rh-negative; her husband is group O, Rh-positive, probably CDe. CDe. No antibodies were found before or immedi¬ ately after delivery of her second baby on October 1, 1965. Her post-delivery blood sample contained 3.2% fetal red cells, determined by the KleihauerBetke technique.7 The baby, a vigorous boy weighing 3500 g., was group B, Rh-positive, direct Coombs' test negative. He showed no clinical signs of anemia although his hemoglobin, 13.0 g. per 100 ml. at 2 hours, dropped to 11.8 g. per 100 ml. at 3 days of age. The volume of fetal blood transfused into his mother was estimated to be 100 ml.