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RH Compatibility
Your blood type contains a factor that determines if it is positive or negative. When you are Rh-negative, your blood contains the negative factor. Fifteen percent of all women have Rh-negative blood. If you are Rh-negative, you may require additional attention during pregnancy and after your baby is born.
In the past, an Rh-negative woman who carried an Rh-positive baby faced complications in pregnancy that could result in a very sick newborn. Today, many of these problems can be prevented.
How It Occurs
Rh incompatibility occurs when a fetus inherits Rh-positive blood from its father; the mother, who is Rh-negative, develops antibodies to the fetus's antigens (substances that stimulate the body's immunities against antibodies). Antibodies are made only when the mother has Rh-negative blood and the fetus has Rh-positive blood. These antibodies circulate inside your system. They don't harm you, but they can cross the placenta and attack the blood cells of an Rh-positive fetus. This can lead to serious problems in the fetus, such as anemia; however, problems are now rare because they can be avoided by using RhoGAM.
If you are Rh-negative, you need to know it. You could become Rh-sensitized, also called isoimmunized, under many other circumstances. (Rh-sensitized means that your antibodies will recognize and attack your baby's Rh-positive blood.) Your chances of becoming Rh-sensitized are increased if any of the following applies to you:
• you have had a blood transfusion with Rh-positive blood
• you have received blood products of some kind -during a normal pregnancy
-with an ectopic pregnancy
-with a miscarriage
-with an abortion
The problem doesn't usually occur with a first pregnancy. A woman does not develop antibodies until her immune system comes in direct contact with Rh-positive blood. This usually doesn't happen until delivery, when the placenta separates from the uterus.
Treatment
Many problems can be prevented with the use of RhoGAM, which is Rh-immune globulin. If you are Rh-negative and pregnant, you will be checked for antibodies at the beginning of pregnancy and at 28 weeks. You'll receive an injection of RhoGAM at 28 weeks to prevent sensitization before delivery. You also receive an injection if you have amniocentesis, a miscarriage, an ectopic pregnancy, an abortion or bleeding during pregnancy.
RhoGAM is a blood product. If you have religious or ethical reasons for not using blood products, discuss the situation with your minister and your physician.
Some women have expressed concern about the risk of contracting hepatitis or HIV from use of RhoGAM, but these problems have not been reported. Donors for Rh-immune globulin are screened carefully to eliminate those in high-risk groups for transmission of infectious diseases. Immune globulins have not been reported to transmit hepatitis, HIV or any other infectious diseases. If you are concerned, talk with your doctor.
If your baby is Rh-positive and you are Rh-negative, you will be given an injection of RhoGAM within 72 hours after delivery. If your baby is Rh-negative, like you, a RhoGAM injection after birth isn't necessary.
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