If your Rh factor is negative

At the beginning of this pregnancy when we determined you do not have the Rh factor in your blood, therefore, you are Rh negative we also tested your blood for antibodies. One of the antibodies we were especially interested in was the antibody developed to protect you from Rh positive blood cells. Unless you have been told otherwise, your antibody screen was normal. We needed this information because we want to prevent your body during this pregnancy from creating any antibodies against Rh positive blood.

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The Rh factor does not affect your general health, but can cause problems during pregnancy. This may occur when an Rh negative mother and an Rh positive father conceive an Rh positive infant. If the positive fetal blood mixes with the mother's negative blood, her blood reacts to the cells as a foreign substance and begins to make antibodies. Once formed, these antibodies do not disappear. They become a permanent part of her defense system. During pregnancy, the antibodies can cross into the fetal blood stream and attack the fetal blood cells, destroying them and causing the infant to become severely anemic. This anemia is known as hemolytic disease.

Hemolytic disease can be prevented if the Rh negative mother has not been sensitized (developed antibodies). This can be accomplished by giving her an injection of a sterilized blood product called Rh immuno globulin (RhoGam). RhoGam works because it is the antibody in a small enough dose not to cause harm but enough to make the mother's body believe she is protected against the invading blood cells. Because her body is not triggered to produce the antibody and RhoGam blood cells die after a time, the mother's body never gets the message to continue to develop the antibody which could harm the fetus. RhoGam is given around the 28th week of pregnancy, and at delivery if the baby is Rh positive. It is also given in any situation where there may be a chance of a mix of maternal and fetal blood, i.e. miscarriage, elective abortion, ectopic pregnancy, first trimester bleeding and amniocentesis. RhoGam is provided with each pregnancy because each time you get pregnant the risk is again present. If this issue applies to you and you have questions please let the clinical staff help you understand the care and treatment of this condition.

Note: This information applies only to Lansing OB/GYN Associates.