Rh Incompatibility Summary There are four major blood types: A, B, O, and AB. The types are based on substances on the surface of the blood cells. Another blood type is called Rh. Rh factor is a protein on red blood cells. Most people are Rh-positive; they have Rh factor. Rh-negative people don’t have it. Rh factor is inherited though genes. When you’re pregnant, blood from your baby can cross into your bloodstream, especially during delivery. If you’re Rh-negative and your baby is Rh-positive, your body will react to the baby’s blood as a foreign substance. It will create antibodies (proteins) against the baby’s blood. These antibodies usually don’t cause problems during a first pregnancy. But Rh incompatibility may cause problems in later pregnancies, if the baby is Rh-positive. This is because the antibodies stay in your body once they have formed. The antibodies can cross the placenta and attack the baby’s red blood cells. The baby could get Rh disease, a serious condition that can cause a serious type of anemia. Blood tests can tell whether you have Rh factor and whether your body has made antibodies. Injections of a medicine called Rh immune globulin can keep your body from making Rh antibodies. It helps prevent the problems of Rh incompatibility. If treatment is needed for the baby, it can include supplements to help the body to make red blood cells and blood transfusions. NIH: National Heart, Lung, and Blood Institute National Heart, Lung, and Blood Institute Clinical Trials ClinicalTrials.gov: Erythroblastosis, Fetal National Institutes of Health Array Fetal-maternal erythrocyte distribution Hemolytic disease of the newborn Rh incompatibility Diagnosis and Tests How Is Rh Compatibility Diagnosed? National Heart, Lung, and Blood Institute Red Blood Cell Antibody Identification American Association for Clinical Chemistry Rh Factor Blood Test Mayo Foundation for Medical Education and Research Treatments and Therapies How Is Rh Incompatibility Treated? National Heart, Lung, and Blood Institute Encyclopedia Hydrops fetalis Children Hydrops Fetalis/Erythroblastosis Fetalis Children’s Hospital and Health System, Wisconsin Rh Incompatibility (For Parents) Nemours Foundation Living With Living with Rh Incompatibility National Heart, Lung, and Blood Institute Find an Expert National Heart, Lung, and Blood Institute National Heart, Lung, and Blood Institute National Institute of Child Health and Human Development National Institute of Child Health and Human Development Journal Articles Rh Incompatibility Start Here Rh Disease March of Dimes Birth Defects Foundation Rh Factor: How It Can Affect Your Pregnancy American College of Obstetricians and Gynecologists Rh Incompatibility National Heart, Lung, and Blood Institute Symptoms What Are the Signs and Symptoms of Rh Incompatibility? National Heart, Lung, and Blood Institute Related Issues Who Is at Risk for Rh Incompatibility? National Heart, Lung, and Blood Institute
