Final answer:
To prevent the development of Rh antibodies and reduce the risk of hemolytic disease of the newborn, an Rh-negative primigravida should receive Rho(D) immune globulin (RhoGAM) during the 28th week of pregnancy and within 72 hours after delivery.
Step-by-step explanation:
Preventing the Development of Rh Antibodies
An Rh-negative primigravida (a woman who is pregnant for the first time) should receive Rho(D) immune globulin (RhoGAM) to prevent the development of Rh antibodies, which can lead to hemolytic disease of the newborn (HDN). This preventive treatment is crucial as it lowers the risk of an immunological response against Rh-positive red blood cells which may enter the maternal circulation from an Rh-positive fetus. RhoGAM is typically administered during the 28th week of pregnancy and within 72 hours after delivery, as well as after any events that could cause fetal-maternal blood exchange.
Without this intervention, there's a risk that the mother will become sensitized and subsequently develop antibodies that could affect future pregnancies with Rh-positive babies. RhoGAM works by providing anti-Rh antibodies that target and destroy any Rh-positive fetal red blood cells before the mother's immune system can react to them, thereby preventing the primary antibody response that could lead to HDN in subsequent pregnancies.