Rhesus isoimmunization occurs when an Rh-negative mother carries an Rh-positive baby and fetal-maternal hemorrhage of Rh-positive fetal red blood cells into the mother's circulation triggers the formation of anti-D antibodies. This can sensitize the mother and cause hemolytic anemia in subsequent Rh-positive pregnancies if the anti-D antibodies cross the placenta and destroy fetal red blood cells. Administering RhoGAM (anti-D immunoglobulin) to the mother during and after pregnancy can prevent sensitization by neutralizing any Rh-positive fetal red blood cells that enter her circulation. Close monitoring and medical management is required for sensitized Rh-negative mothers to prevent harm to