Rho(D) immune globulin

Rho(D) immune globulin (RhIG) is a medication used to prevent RhD isoimmunization in mothers who are RhD negative and to treat idiopathic thrombocytopenic purpura (ITP) in people who are Rh positive. It is often given both during and following pregnancy. It may also be used when RhD-negative people are given RhD-positive blood. It is given by injection into muscle or a vein. A single dose lasts 12 weeks. It is made from human blood plasma. Common side effects include fever, headache, pain at the site of injection, and red blood cell breakdown. Other side effects include allergic reactions, kidney problems, and a very small risk of viral infections. In those with ITP, the amount of red blood cell breakdown may be significant. Use is safe with breastfeeding. Rho(D) immune globulin is made up of antibodies to the antigen Rho(D) present on some red blood cells. It is believed to work by blocking a person's immune system from recognizing this antigen. Rho(D) immune globulin came into medical use in the 1960s, following the pioneering work of John G. Gorman. In 1980, Gorman shared the Lasker-DeBakey Clinical Medical Research Award for pioneering work on the rhesus blood group system. RhIG is on the World Health Organization's List of Essential Medicines. In a pregnancy where the mother is RhD negative and the father is RhD positive, the probability of the fetus having RhD positive blood is dependent on whether the father is homozygous for RhD (i.e., both RhD alleles are present) or heterozygous (i.e., only one RhD allele is present). If the father is homozygous, the fetus will necessarily be RhD positive, as the father will necessarily pass on a Rh D positive allele. If the father is heterozygous, there is a 50% chance that the fetus will be RhD positive, as he will randomly pass on either the RhD positive allele or not. If a fetus is RhD positive and the mother is RhD negative, the mother is at risk of RhD alloimmunization, where the mother mounts an immune response (develops antibodies) to fetal red blood cells.