ABO and Rh incompatibilities are abnormal reactions that occationally occur when a pregnant woman's blood type does not match the blood type of her baby. This may result in the destruction of the baby's red blood cells.
There are two major outcomes of incompatibility: the mother's blood will make antibodies to attack foreign proteins in the baby's blood. The medical term for this is Erythroblastosis fetalis. Once the antibodies attack the baby’s red blood cells, anemia (low red blood cell count) will occur. This condition is known as Hemolytic anemia.
Blood has two important classifications:
ABO Blood Typing
Jaundice - yellow coloring of skin
ABO blood typing was not diagnosed until about 100 years ago, when physician Karl Landsteiner decided to investige why some patients were saved by blood transfusions and others died in the process. His discovery of blood antigens won him the Nobel Prize over 30 years later.
The Rh factor is named after the Rhesus monkey, because while using monkey blood to develop an antiserum that would differentiate between blood types, some of the blood began to clot. Your blood is said to be Rh+ if it clots when exposed to the antiserum. If not, you have Rh- blood.