If a fetus is RhD positive and the mother is RhD negative, the mother is at risk of RhD alloimmunization, where the mother mounts an immune response (develops antibodies) to fetal red blood cells. This usually has minimal effect on the first such pregnancy; but, in a second such pregnancy, pre-existing maternal antibodies to RhD antigens on fetal red blood cells often leads to erythroblastosis fetalis, a condition which can be fatal to the fetus. In countries without Rh immune globulin (RhIG) protocols, as many as 14% of affected fetuses are stillborn and 50% of live births result in neonatal death or brain injury.