Final answer:
Hemolytic disease of the newborn typically becomes a problem in second or subsequent pregnancies with an Rh-positive fetus due to the mother's prior sensitization and production of anti-Rh antibodies. Rh-negative mothers receive Rho(D) immune globulin to prevent this condition. Indirect Coombs' test is used for the mother and direct Coombs' test for the newborn to detect HDN.
Step-by-step explanation:
Hemolytic disease of the newborn (HDN), also known as erythroblastosis fetalis, occurs when there is an incompatibility between the Rh blood group antigens of the mother and fetus. When an Rh-negative mother carries an Rh-positive fetus, there is a risk of her immune system attacking the fetal red blood cells. This condition becomes a problem primarily during second or subsequent pregnancies with an Rh-positive fetus because the mother would have been sensitized during the first pregnancy, leading to the development of anti-Rh antibodies. These antibodies can cross the placenta in future pregnancies and potentially cause hemolysis of fetal red blood cells, leading to anemia or more severe complications.
To prevent HDN, Rh-negative mothers are treated with Rho(D) immune globulin, which is administered during the 28th week of pregnancy and within 72 hours after childbirth to prevent the immune response against Rh-positive fetal blood cells. The indirect Coombs' test is used to screen the mother's blood for these antibodies before birth, while the direct Coombs' test is performed on the newborn's blood to confirm the presence of antibodies attached to the red blood cells, which is indicative of HDN.