Final answer:
Erythroblastosis fetalis is a condition where a Rh-negative mother develops antibodies against Rh-positive fetal blood, causing anemia in subsequent pregnancies. It is treated with anti-Rh antibodies given during the first pregnancy.
Step-by-step explanation:
Erythroblastosis fetalis, also known as hemolytic disease of the newborn, is a condition that occurs when a mother who is Rh-negative has multiple children with an Rh-positive father. During the first birth, fetal blood enters the mother's circulatory system, causing her to produce anti-Rh antibodies. The condition is treated by giving the mother anti-Rh antibodies (RhoGAM) during the first pregnancy, which prevents the production of anti-Rh antibodies.