RH INCOMPATIBILITY

General Information

DEFINITION--Incompatibility between an infant's blood type and that of the mother, resulting in destruction of the infant's red blood cells (hemolytic anemia) after birth by antibodies from the mother's blood.

BODY PARTS INVOLVED--Blood of pregnant mother and fetus.

SEX OR AGE MOST AFFECTED--Newborn infants only.

SIGNS & SYMPTOMS

Signs during pregnancy:

• Decreased fetal growth.
• Decreased fetal movement.

Signs in a newborn:

• Paleness.
• Jaundice (yellow skin and eyes) that begins within 24 hours after delivery.
• Unexplained bruising or blood spots under skin.
• Tissue swelling (edema).
• Breathing difficulty or seizures.
• Lack of normal movement; poor reflexes.

CAUSES--The fetus of an Rh-negative (blood type) mother and an Rh-positive father may be Rh-positive. During delivery, a small amount of the infant's blood is absorbed by the mother through the placenta, stimulating her body to produce antibodies against Rh-positive blood. The antibodies are produced after delivery, so the first infant is not affected. With succeeding pregnancies, the antibodies in the mother's blood destroy fetal blood cells. In pregnancy, anti-Rh antibodies cross the placenta and destroy fetal blood cells. The resulting anemia can cause fetal death. If the fetus survives, antibodies can cross to baby during birth, producing jaundice and other symptoms.

RISK INCREASES WITH

• Each pregnancy after the first involving different blood types.
• Previous blood transfusions. These might have contained unidentified, incompatible blood types.

HOW TO PREVENT

• Obtain prenatal care throughout pregnancy. Early care is essential to determine the risk of Rh incompatibility.
• Special anti-Rh gamma globulin is given to the mother at 28 weeks gestation and within 72 hours after delivery, miscarriage, ectopic pregnancy or abortion. This prevents formation of antibodies that might affect future infants.
• Amniocentesis beginning at 28 weeks if indicated by elevated antibody titers in the mother.

What To Expect

DIAGNOSTIC MEASURES--

• Medical history and physical exam by a doctor. Tell your doctor if you have had a miscarriage or abortion.
• Blood tests to: type mother's, father's and infant's blood; measure the mother's Rh-positive antibodies; and detect hemolytic anemia in the infant's blood.
• Amniocentesis (See Glossary).

APPROPRIATE HEALTH CARE

• Doctor's treatment.
• Intrauterine transfusions (sometimes).
• Transfusion to exchange completely the infant's blood after birth.
• Hospitalization.

POSSIBLE COMPLICATIONS

• Permanent neurological damage.
• Blood-transfusion reaction.

PROBABLE OUTCOME--With prompt recognition of the disorder, damage to the infant can be prevented with exchange transfusions.

How To Treat

GENERAL MEASURES----If you have an Rh-negative blood type:

• Tell any doctor or medical professional who treats you. Make sure this information is in your medical records.
• Wear a Medic-Alert bracelet or pendant (See Glossary).

MEDICATION--If you are pregnant and have Rh-negative blood type, you will be prescribed an anti-Rh gamma globulin injection at 28 weeks and again within 72 hours after delivery or termination of a pregnancy for any reason. You may also have antibody titer drawn during pregnancy to see if you are producing anti-Rh antibodies.

ACTIVITY--No restrictions after treatment.

DIET--The infant may be breast-fed or bottle-fed normally.

Call Your Doctor If

Your baby has any of the following after returning home:

• Fever or jaundice (yellow skin or eyes).
• Poor appetite or poor weight gain.
• Excessive crying that does not stop when the baby is held.