Rh Factor in Pregnancy

During your first prenatal visit, your health care provider will take blood samples. Several things will be tested, including your blood type. The reason this is done is to check for the presence or lack of Rh factor in the blood. This is important because if your baby has Rh factor in his blood and you do not, this could cause problems in later pregnancies.

 

What is Rh factor and why does it matter? When you are told your blood type, the letter A, B, AB or O will be followed by a positive or negative. Rh is basically a protein that is present on the blood cells. Most people do have Rh factor, but about 15 percent of people do not. The positive, such as B+, means that Rh factor is present in the blood. If the blood type were O-, there would be no Rh factor in the blood. This is generally never a problem, unless you are an Rh negative mother with an Rh positive partner.

 

In this case, the baby’s blood type may not have the same Rh status as yours, for example the baby may be Rh positive and mom is Rh negative. There are times when the baby’s blood can enter the mother’s blood stream. When this happens, the mother’s body will begin to make antibodies against the Rh factor in the baby’s blood. The baby is basically seen as an intruder to the body.

 

These antibodies made by the mother’s body generally do not cause a problem in the first pregnancy. However, the antibodies remain after the baby is born. The presence of these antibodies can cause a problem in the second or subsequent pregnancies, if the mother is not treated.

 

The treatment in this case is to give the mother an injection of Rh immunoglobulin or Rhogam. This is given to suppress the body’s reaction against the Rh positive blood cells of the baby and future babies. In some cases, the injection may be given to prevent problems in the current pregnancy. This is sometimes done when the mother has had a previous pregnancy that ended in miscarriage, since the mother may have been sensitized at that time.

 

In this case, the first injection will be given at about 28 weeks of pregnancy. The second shot will be given in the hospital after the baby is born. More doctors are going to this method, rather than waiting until after the baby is born. If the mother experiences any type of bleeding in early pregnancy, the doctor will most likely proceed with the Rhogam injection during pregnancy.

 

The treatment with Rhogam is very important for a woman’s future babies. Without treatment, her body will attack the next baby’s positive blood cells. This can lead to a condition known as hemolytic disease. When the baby’s blood cells are attacked, this can lead to anemia, brain damage, heart failure or still birth.

 

For more information on Rh factor visit the American Pregnancy Association: http://www.americanpregnancy.org/prenataltesting/rhfactor.html