When you are pregnant, you will have a blood test to find out what blood type you are. When a pregnant women is Rh-negative, it means that she does not have the Rh factor or antigen (a specific protein in red blood cells). The father of the baby will also be tested for his blood type. If he is Rh-negative also, the baby will be Rh-negative. In this case, no Rh problems will develop during the pregnancy, and RhoGAM will not be needed. If the father is Rh-positive, it is possible that the baby will be Rh-positive, which is incompatible with the mother's Rh-negative blood. In this case, the mother's blood will react as though she is allergic to the baby's blood. Her body will produce antibodies to destroy the baby's red blood cells. This causes anemia, brain damage, and even death of the baby.

RhoGAM (anti-Rh, anti-D immunoglobulin) is a vaccine or immunization produced from human plasma. It is given to Rh-negative women who have Rh-positive babies, to protect the babies of future pregnancies. Firstborn infants are usually not affected, because it takes time for the mother's body to develop the antibodies. About 15% of people are Rh-negative.


In a normal pregnancy, small numbers of the baby's red blood cells get into the mother's bloodstream. When the baby is Rh-positive, the mother's immune system (body system that fights infections and illness) recognizes that the blood is different from her own. The mother's body tries to fight it off and destroy it, like fighting off an infection or illness. The mother's immune system forms antibodies against the baby's blood. These antibodies are passed through the placenta to the baby, and they begin to destroy the baby's red blood cells. The baby becomes anemic (lacking enough red blood cells). The Rh problem does not usually affect the first baby. If the mother does not get RhoGAM, each of the following pregnancies gets more dangerous, if the future babies are Rh-positive. That is because the mother's immune system develops more antibodies each time. It gets stronger and increases the number of antibodies against the baby's red blood cells with each future pregnancy.


RhoGAM is a solution containing small amounts of Rh antibodies. It prevents the development of antibodies against Rh-positive blood. It is injected into the mother at around 7 months of pregnancy, if she is Rh-negative. It is injected again within 72 hours after the baby is born, if the baby is Rh-positive. It is also given anytime during the pregnancy, if uterine bleeding develops. RhoGAM does not hurt the baby. It has few and minor side effects, if any, to the mother. A MICRhoGAM (smaller dose) is given in case of a miscarriage, elective abortion, or tubal pregnancy (pregnancy outside the uterus) if it is before 13 weeks of the pregnancy.

RhoGAM should be given in the event of:

  • Miscarriage.

  • Threatened miscarriage, if there is bleeding.

  • Induced abortion.

  • Tubal (ectopic) pregnancy.

  • Any bleeding during the pregnancy.

  • Taking an amniotic fluid sample (amniocentesis).

  • Blood sampling.

  • Getting the wrong blood transfusion (positive blood in an Rh-negative woman).

  • Moving the baby from breech to normal position (external version).

  • Taking a placenta tissue sample (chorionic villus sampling).

  • Taking a blood sample from the umbilical cord (cordocentesis).

  • Mass of cysts in the uterus, instead of a fetus (hydatidiform mole).

  • Failure to get RhoGAM when necessary.

  • Pregnancy lasting past the due date, when the last RhoGAM shot was given 12 weeks ago.

  • Injury (trauma) to the abdomen.

RhoGAM should be given even if the Rh-negative mother has a tubal ligation (female sterilization, "tied tubes"). This is because some women will later decide to have surgery to re-open the tubes, in order to get pregnant again. Or the tubal ligation might not work.

RhoGAM is given after the delivery of an Rh-positive baby to an Rh-negative mother. It only protects the baby in the next pregnancy. RhoGAM must be given after each delivery of an Rh-positive baby born to an Rh-negative mother. RhoGAM cannot help a pregnant Rh-negative mother if she has already been sensitized with Rh-positive antibodies.

RhoGAM is not known to transmit hepatitis or other infectious diseases. Your caregiver can discuss the recommendations and uses of RhoGAM with you. You should not receive RhoGAM if you had an allergic reaction to it in the past.