Treating Rh Sensitization

Treating Rh Sensitization

What to do when the fetus is allergic to its mother’s blood

When a pregnant woman’s blood lacks a protein called the Rh factor which helps trigger certain of the body’s immune responses, and the father’s blood contains that protein, the fetus’ blood can end up being incompatible with the mother’s blood. When that happens, the mother’s body may act as if it were allergic to the fetus and produce antibodies that attack the fetus’s red blood cells, resulting in anemia.

Known as hemolytic or Rh disease, the condition can be serious enough to cause death in the fetus or newborn. The condition occurs in about one in twenty pregnancies.

The best way to prevent this reaction is to inject the mother with a blood product called Rh immunoglobulin (Rhlg) before her body has had an allergic reaction to the fetus’s blood. Such a reaction, which is also known as sensitization, can occur any time the mother’s and fetus’s blood mix. (One prime chance for this to happen is during amniocentesis).

A protected lady. Photo by Elena

The protection from Rhlg usually lasts about twelve weeks, which means that the treatment may need to be repeated several times during a pregnancy.

Should sensitization occur and antibodies from the mother begin to attack the fetus’s blood, there is nothing Rhlg injections can do to remove these antibodies. The doctor will have to monitor the level of antibodies closely, and to conduct special tests on the fetus if too many antibodies are detected.

If anemia is found, the fetus may require a blood transfusion in the uterus, or if the mother is close enough to term, early delivery and treatment in an intensive-care nursery.