Hemolytic Disease

Elizabeth High

Hemolytic Disease of the Newborn

Hemolytic disease of the newborn (HDN)   is when a mother’s antibodies cross the placenta, attacking and destroying fetal RBCs. The most fatal cases are those in which the RH surface antigen are involved. When an Rh-negative mother becomes pregnant with an Rh-positive child, the mother's immune response to the fetal Rh antigen is to form antibodies against it (anti-Rh). These antibodies are transported across the placenta and delivered to the fetal circulation. Exposure to fetal red blood cell antigens happens at delivery when bleeding takes place at the placenta and uterus.   This mixing of blood is the first time the mothers’ immune system produces the anti-Rh antibodies. This process is called sensitization. Once sensitization occurs, the mothers serum will contain the anti-Rh antibodies. The first Rh positive child that a mother carries will not be affected by HDN since the anti-Rh antibodies are not produced in the mother until 6 months after delivery. But the next baby that the mother has is a Rh positive fetus, the mothers anti Rh antibodies will cross the placenta and enter the bloodstream. These antibodies destroy fetal RBCs and cause severe anemia. The fetus demands more blood cells and has to resort to taking from the bone marrow before the bone marrow is fully developed. If the fetus is not treated, it will most likely die before delivery. A newborn with severe HDN will be anemic and the high concentration of bilirubin will cause it to have jaundice. All of an infants blood will have to be replaced in order to remove all the materiality Rh antibodies as well as the affected RBCs. If the fetus is not going to live to full term, doctors might induce labor at 7-8 weeks. The maternal production of anti-Rh antibodies can be stopped in their tracks with an administration of antibodies to the mother in the last 3 months of pregnancy and during and after delivery. These antibodies will destroy all fetal...