RhoGAM is administered at 28 weeks gestation to reduce hydrops fetalis due to which condition?

• A. Rh isoimmunization (correct)
• B. ABO incompatibility
• C. Twin-to-twin transfusion
• D. Anemia of prematurity

Answer: (A)

Prevention of maternal sensitization to the Rh(D) antigen to avoid hemolytic disease of the fetus and newborn that can lead to hydrops fetalis.

RhoGAM contains anti-D immune globulin. In an Rh-negative mother, small amounts of Rh-positive fetal red blood cells can enter maternal circulation during pregnancy or delivery. The passive anti-D antibodies in RhoGAM bind these cells and promote their clearance before the mother’s immune system encounters the Rh(D) antigen, preventing formation of anti-D antibodies (sensitization). By preventing this sensitization, the risk of Rh isoimmunization in this and future pregnancies—and thus hydrops fetalis due to Rh disease—is reduced. RhoGAM does not prevent ABO incompatibility, which is caused by different antibodies and can still occur. Conditions like twin-to-twin transfusion and anemia of prematurity are unrelated to Rh sensitization and are not addressed by RhoGAM. Postpartum RhoGAM is given if the newborn is Rh-positive and the mother is Rh-negative.