Blood transfusion: If a patient with Rh negative (Rh-ve) blood group receives Rh positive (Rh+ve) blood, there is no problem the first time. However, Rh antibodies develop in his blood within the second week. Later, if the patient receives Rh positive (Rh+ve) blood, his red blood cells are destroyed due to Rh antibodies. Patients may die with various complications.
In pregnancy: If a woman with Rh negative (Rh-ve) blood is married to a man with Rh positive (Rh+ve) blood, the first child will be Rh positive (Rh+ve). During this time, Rh antibodies are created in the mother’s blood. Later during pregnancy, the previously produced Rh antibodies are transferred from the mother’s blood to the fetus through immortality. In this the red blood cells of the fetus are destroyed and the child dies.