In Rh incompatibility, which maternal-fetal combination necessitates the use of Rho(D) immune globulin after birth?

In Rh incompatibility, which maternal-fetal combination necessitates the use of Rho(D) immune globulin after birth?

• A. Maternal Rh-positive status with an Rh-negative fetus
• B. Maternal Rh-negative status with an Rh-positive fetus
• C. Maternal Rh-positive status with an Rh-positive fetus
• D. Maternal Rh-negative status with an Rh-negative fetus

Answer: (B)

The key idea is preventing the mother from becoming sensitized to the Rh D antigen after exposure to fetal Rh-positive cells during delivery. When an Rh-negative mother delivers an Rh-positive baby, fetal red cells can enter the maternal circulation. If this happens, the mother may develop anti-D antibodies, which can cause hemolytic disease in future pregnancies. Administering Rho(D) immune globulin postpartum neutralizes any fetal Rh-positive cells in the mother’s blood, preventing sensitization and protecting future pregnancies. This is why the postpartum dose is recommended in the scenario where the mother is Rh-negative and the newborn is Rh-positive. In other combinations, there isn’t the same risk of new anti-D formation: an Rh-positive mother already recognizes the D antigen as self, and an Rh-negative mother with an Rh-negative baby has little to no exposure to D antigen.

The key idea is preventing the mother from becoming sensitized to the Rh D antigen after exposure to fetal Rh-positive cells during delivery. When an Rh-negative mother delivers an Rh-positive baby, fetal red cells can enter the maternal circulation. If this happens, the mother may develop anti-D antibodies, which can cause hemolytic disease in future pregnancies. Administering Rho(D) immune globulin postpartum neutralizes any fetal Rh-positive cells in the mother’s blood, preventing sensitization and protecting future pregnancies.

This is why the postpartum dose is recommended in the scenario where the mother is Rh-negative and the newborn is Rh-positive. In other combinations, there isn’t the same risk of new anti-D formation: an Rh-positive mother already recognizes the D antigen as self, and an Rh-negative mother with an Rh-negative baby has little to no exposure to D antigen.