Mother-fetus incompatibility

                      occurs when the mother is Rh- (dd) and the father is Rh+ (DD or Dd).  Maternal antibodies can cross the placenta and destroy fetal red blood cells.  The risk increases with each pregnancy.  Europeans are the most likely to have this problem--13% of their newborn babies are at risk.  Actually only about ½ of these babies (6% of all European births) have complications.  With preventive treatment, this number can be cut down even further.  Less than 1% of those treated have trouble.  However, Rh blood type incompatibility is still the leading cause of potentially fatal blood related problems of the newborn. The first time an Rh- woman becomes pregnant, there usually are not incompatibility difficulties for her Rh+ fetus.  However, the second and subsequent births are likely to have life-threatening problems.  The risk increases with each birth