A RhoGAM® injection is an injection of Rh0 immunoglobulin which is given to a woman to prevent the formation of antibodies to Rh positive blood. This medication is used to prevent a complication of pregnancy known as Rhesus disease or hemolytic disease of the newborn. Women should receive a RhoGAM® injection within 72 hours of delivery, miscarriage, or termination of pregnancy if their blood is Rh negative to avoid complications in future pregnancies.
Rhesus disease is a complication caused by conflicts between blood types in the Rhesus grouping. If a woman's blood does not carry the D factor from the Rhesus grouping system, she is said to be Rh negative. If the father of a baby has the D factor, he is Rh positive, and there is a risk that the baby will be Rh positive as well. Exposure to Rh positive blood will trigger the production of antibodies, as the immune system recognizes it as a threat, which means that an Rh negative woman with a history of exposure to Rh positive blood who is pregnant with an Rh positive child could be at risk of complications because her immune system could attack the fetus.
There are two ways in which Rh negative women can be exposed to Rh positive blood. One is through a blood transfusion, although steps are taken to avoid this. The other way is through the blood of an Rh positive fetus; women who have any kind of pregnancy, whether it is terminated or carried to term, will be exposed to the fetal blood, and women can also be exposed to fetal blood as a result of abdominal trauma or during amniocentesis testing.
If a doctor believes that an Rh incompatibility might occur, she or he will recommend a RhoGAM® injection during the 28th week of pregnancy, and again after delivery. Women who miscarry and are Rh negative should also have the injection, as should women who terminate pregnancies. The injection is also recommended after amniocentesis or abdominal trauma. The RhoGAM® injection will eliminate the anti-D antibodies in the mother's blood so that if she becomes pregnant again, the baby will not be at risk.
Rhesus disease was once a very serious problem. Once the RhoGAM® injection was introduced in the 1960s, rates of Rhesus incompatibility during pregnancy declined radically, reducing risks to both mothers and babies. Today, doctors usually screen early in pregnancy for the signs of Rhesus incompatibility, typing the blood of both parents, if possible, and interviewing the mother to identify any risk factors.
Rhesus incompatibility is not an issue for Rh positive mothers with Rh negative babies.