An Rh-negative mother who was exposed to her fetus's Rh-positive blood during a previous pregnancy or delivery or who has accidentally received an Rh-positive blood transfusion has antibodies against Rh-positive blood cells.
Rh disease, for example, has been controlled by the advent of anti-Rh globulin; its administration to Rh-negative mothers has reduced one risk factor for CP.
Rh disease in the newborn is rare in developed countries due to routine screening of maternal blood type and routine prevention of anti-Rh antibodies in Rh negative women after each birth of an Rh positive infant.
Complications may arise if an Rh-negative mother is carrying an Rh-positive child.
Rh incompatibility may develop when a woman with Rh-negative blood becomes pregnant by a man with Rh-positive blood and conceives a fetus with Rh-positive blood.
