Final answer:
Hemolytic disease of the newborn (HDN), also called erythroblastosis fetalis, occurs when an Rh-negative mother's previously formed anti-Rh antibodies attack the red blood cells of a subsequent Rh-positive fetus. To prevent this condition, Rh-negative mothers receive Rho(D) immune globulin injections to prevent the formation of these harmful antibodies. Without treatment, the consequences for the fetus can include anemia, brain damage, or death.
Step-by-step explanation:
Hemolytic disease of the newborn (HDN), also known as erythroblastosis fetalis, is a condition that occurs when an Rh-negative mother has formed anti-Rh antibodies during a previous pregnancy with an Rh-positive child. During a subsequent pregnancy with an Rh-positive fetus, these antibodies can cross the placenta and attack the fetal red blood cells, leading to hemolysis, or the destruction of these cells.
To prevent the disease, Rh-negative mothers are given an injection of Rho(D) immune globulin, which targets any Rh-positive fetal blood cells that may enter her system, thereby preventing the formation of anti-Rh antibodies. Without this preventive treatment, the antibodies produced during a first pregnancy can severely affect the health of a second Rh-positive fetus, possibly leading to anemia, brain damage, or even fetal death.
Maternal exposure to Rh-positive fetal red blood cells typically occurs during the last trimester of pregnancy or delivery. In cases of such incompatibility, the first Rh-positive baby is usually unaffected, as the maternal immune response may not be fully developed before birth. However, subsequent pregnancies are at risk and require prophylactic treatment.