We all inherit a blood type, (example A, B, O, AB,) that is either Rh+ (positive has the dominant factor) or Rh- (negative lacks the factor). At your initial OB visit, your blood type was checked to determine your Rh type. It is especially important to identify pregnant women with Rh negative blood type.
During a pregnancy the fetus inherits its blood type. If the mother is Rh negative and the baby is Rh positive, there is a chance that the mother may produce antibodies (protein in the blood) that fight the foreign Rh positive blood. This is not a problem for the current pregnancy since the mom cannot make enough of the antibody to harm the current baby. The problem occurs in future pregnancies if the new child has Rh positive blood and the mom has enough antibodies to fight this new fetus.
To prevent this future complication, all Rh negative pregnant women receive a medicine called Rhogam. This medicine stops the antibody production so that future pregnancies will not be affected. A mother should receive Rhogam standard at 28 weeks of pregnancy and after delivery if the baby has Rh positive blood (this is checked after the baby is born). Other times a woman may need Rhogam is if she bleeds during the pregnancy, if she has a miscarriage, or if she has any invasive procedures such as an amniocentesis.
If you have any concerns about your Rh status or receiving the Rhogam injection, feel free to
discuss this with your provider.