Acquisition of anti‐Diego b antibodies possibly resulting from feto‐maternal hemorrhage during pregnancy

Anti-Diego b (Di(b) ) antibodies, rare antibodies against red blood cell antigens, can cause severe hemolysis. We report a patient who most likely acquired anti-Di(b) antibodies during pregnancy. The patient was a 39-year-old Japanese woman who delivered by cesarean section at 38 weeks of gestation. She required a second operation to treat re-bleeding of the surgical scar, but it was difficult to schedule this surgery because we could not obtain enough blood for transfusion due to the presence of anti-Di(b) antibodies. These antibodies were likely acquired during pregnancy; she did not have irregular antibodies at 11 weeks of gestation. We speculate that she became sensitized to fetal blood due to feto-maternal hemorrhage. The infant had no hemolytic conditions. Testing for the presence of irregular antibodies should be performed during late stages of pregnancy as well as early stages.