For Patients/Families

Hemolytic disease of the newborn
Condition in which mother and baby have different blood types. A woman who has a different blood type than her fetus may occasionally produce antibodies against the fetus’ blood cells. This is usually caused by Rh incompatibility, although other types of incompatibility can rarely cause hemolytic disease.

During pregnancy, a few of the baby’s red blood cells pass through the placenta into the mother’s bloodstream. In Rh incompatibility, the mother’s immune system recognizes these red blood cells as incompatible and “foreign.” She then begins making antibodies to her own baby’s red blood cells. These antibodies cross the placenta and attack and destroy the baby’s red blood cells. This leads to fetal anemia and even heart failure before delivery. After delivery, this incompatibility can result in continued red blood cell breakdown and high bilirubin concentrations.

Before delivery, Rh incompatibility can be treated with intrauterine blood transfusions to correct the anemia. Although there is some risk to this procedure, it can be very effective in helping to postpone delivery and improve the condition of the infant at delivery. Hemolytic disease of the newborn often leads to premature delivery and the need for neonatal intensive care. After delivery these infants almost always require intensive phototherapy to reduce their bilirubin levels. Sometime they have such high levels of bilirubin that an exchange transfusion is required. They are also more prone to have immature lungs if delivered prematurely.

Although all of these problems are treatable, prevention is better than the best treatment. Your doctor will test your blood type and screen for the presence of potentially dangerous antibodies as part of your routine prenatal care. If you are Rh-negative, you will probably receive a special antibody preparation, Rhogam, that reduces the likelihood you will develop antibodies to fetal red blood cells. You should discuss this issue with your doctor if your blood type is Rh-negative.