42% a, 9% b, 3% ab and 46% o. Europeans: 85% rh positive and 15% rh negative. Asians, africans, native americans: 99% rh positive and 1% rh negative. Connection between rh factor (d antigen) and pregnancy. Rh- individuals normally do not have anti-d antibodies. Transfusion of an rh- negative individual with rh+ blood and pregnancy of rh- mother and rh+ baby can trigger an immune response. ** the fetus is probably not likely to mount an immune response (ie. if the reverse was true, it would not be as big of an issue) ** Inject anti-d antigen antibodies into rh- mother during and following her pregnancy. Different kind of class; doesn"t readily cross to the fetus. These antibodies bind to and remove fetal rbc in the mother"s bloodstream before they can trigger an immune response in the mother. We don"t want the mother to mount an immune response.