Erythroblastosis fetalis is a potentially life-threatening blood disorder in a fetus or newborn infant. This article provides a general overview. For more detailed information see the specific disorder:

• ABO incompatibility
• Rh incompatibility

Erythroblastosis fetalis develops in an unborn infant when the mom and the baby have different blood types. The mother produces substances called antibodies that attack the developing baby's red blood cells.

The most common form of erythroblastosis fetalis is ABO incompatibility, which can vary in its severity.

The less common form is called Rh incompatibility, which more often causes a very severe anemia in the baby.

Symptoms in a newborn baby may include:

• Anemia
• Enlarged liver or spleen
• Generalized swelling
• Newborn jaundice

Specific tests depend on the type of erythroblastosis, but may include:

• Complete blood count
• Bilirubin level
• Blood typing

After birth, depending on the severity, a transfusion usually needs to be performed.

For specific treatment information see:

• ABO incompatibility
• Rh incompatibility

The severity of this condition can vary widely. In some instances, the baby has no symptoms of the disease. In other cases, it can lead to death of the baby before or shortly after birth. It can be treated before birth by intrauterine transfusion.

Complications depend on the specific type of erythroblastosis fetalis.

The most severe form of this disease, Rh incompatibility, can be prevented if the mother takes a medicine called RhoGAM at certain times during and after pregnancy. If you have had a baby with this disease, be sure to talk with your doctor if you plan on having another baby.