You won't believe these 10 facts about people. 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.