Learning About Rh Immune Globulin Treatment During Pregnancy

Rh factor is a protein. It's on the surface of red blood cells. If your blood cells have this protein, you are Rh positive. If they do not, you are Rh negative.

Rh incompatibility can happen when you are pregnant and Rh negative and your baby is Rh positive.

This is a problem because during pregnancy or birth, a small amount of your baby's blood can get into your blood. If that happens, your immune system may make antibodies against the Rh positive cells.

These antibodies can cross the placenta and destroy your baby's red blood cells. This can cause serious health problems. One problem is hemolytic disease of the fetus and newborn (HDFN). HDFN can lead to anemia or jaundice in your baby. It can also lead to too much fluid buildup in your baby before birth. In some cases, the baby may develop brain damage or may die.

Once these antibodies form, they stay in your body for life. They can affect future pregnancies if your baby is Rh positive.

Rh immune globulin is a medicine. It's used to prevent Rh incompatibility during pregnancy. It's made from carefully screened human plasma, the liquid part of blood.

It can stop your body from making Rh antibodies. But it works only if your body has not made them yet. It does not work after they have already formed.

Rh immune globulin given during pregnancy and after birth greatly lowers your chance of making Rh antibodies.

It's given as a shot. If you are Rh negative, you will usually get the shot around 28 weeks of pregnancy. A second dose is usually given within 72 hours after birth if your baby is Rh positive.

You may need extra doses after events that make it more likely for your blood and your baby's blood to mix. These include:

• A miscarriage or pregnancy loss.
• An abortion.
• An ectopic pregnancy (a pregnancy that happens outside the uterus).
• Certain tests or procedures, such as amniocentesis, fetal blood sampling, or fetal surgery.
• An injury to your belly.
• Attempts to turn a baby who is in a breech (feet-first or bottom-first) position.
• Heavy vaginal bleeding during pregnancy.

Your doctor will decide if you need extra doses based on your pregnancy and health.

If you are Rh negative and have not received Rh immune globulin and your blood mixes with the Rh positive blood of your baby, you may make Rh antibodies.

Once your body makes these antibodies, the medicine can no longer prevent them. These antibodies can harm the red blood cells of the baby you are carrying now. They can also attack the red blood cells of an Rh positive baby in a future pregnancy.

If your body makes Rh antibodies, the pregnancy may need extra checkups or closer monitoring by a specialist. Some babies may need special treatment before or soon after birth.

Getting Rh immune globulin when your doctor recommends it is the best way to help prevent these problems.

Rh immune globulin has been used safely for many years.

Common side effects are usually mild. They may include:

• Soreness or redness where you got the shot.
• Mild fever.
• Headache.
• Feeling tired or unwell.

Serious allergic reactions are rare, but they can happen. Contact your doctor right away if you have signs of a serious allergic reaction after getting Rh immune globulin. Signs can include hives or a spreading rash, itching, trouble breathing, or swelling of the face, lips, tongue, or throat.

Rh immune globulin is considered very safe for the baby and the pregnancy. Studies have found no signs that it causes lasting harm to the baby's blood, development, or immune system.