Preventing Rh Disease in Your Baby

Rh factor is a substance most people have in their blood, which makes them Rh positive. Some people are Rh negative. They don't have the Rh factor. On its own, this doesn't cause health problems. But when a mother is Rh negative and the fetus is Rh positive, there can be health risks for the fetus.

• If the mother is Rh negative and the father is Rh positive, their fetus may end up being either Rh negative or Rh positive.

• If the the fetus is Rh positive, there could be a problem if the fetal Rh positive blood mixes with the mother's Rh negative blood.

• Left untreated, the mother's blood will make antibodies that attack the Rh positive blood of the fetus.  This can cause serious health problems for the fetus, including jaundice, anemia, brain damage and even death.

When Are You Treated?

A simple blood test shows if you're Rh negative. This test is done very early in your pregnancy. If you're Rh negative, you'll have a second blood test near week 28 of pregnancy. This test will check whether or not your blood contains Rh antibodies.

If your blood has not formed Rh antibodies, you'll be treated during week 28 of your pregnancy. You'll also be treated any time there's a chance that fetal blood has mixed with yours (for example, after amniocentesis, a prenatal test). Your treatment will be an injection of a medicine called RhoGam. RhoGam prevents Rh antibodies from forming. It won't harm you or the fetus.

After you give birth, your baby's blood will be tested. If it's Rh positive, you'll be given RhoGam again within 3 days. If it's Rh negative, you won't need RhoGam until your next pregnancy.

Preventing Future Problems

Your chance of forming Rh antibodies increases with each pregnancy. That includes ectopic pregnancy (the fertilized egg is outside the uterus) and pregnancy that ends in miscarriage or abortion. In these cases, you should talk with your doctor about getting a RhoGam injection. This is because your body can make Rh antibodies even if you don't deliver a baby.  Rh antibodies can cause problems in future pregnancies.

If You Have Rh Antibodies

If antibodies have already formed (sensitization), RhoGam can't protect the fetus. You and the fetus will need special care during pregnancy. Your health care provider will explain the details to you.

If You're Rh Negative

If you're Rh negative, ask your doctor about getting treated with RhoGam. Even if you miscarry or don't deliver the baby, you will still need treatment. The health of any baby you have in the future depends on it.