Overview
Introduction
Maternal‑fetal Rh incompatibility remains the leading preventable cause of hemolytic disease of the fetus and newborn (HDFN) in Canada.
Maternal‑fetal Rh incompatibility remains the leading preventable cause of hemolytic disease of the fetus and newborn (HDFN) in Canada. When an Rh‑negative mother is exposed to even a microscopic amount of Rh‑positive fetal red cells, her immune system can mount an anti‑D response that destroys red cells in subsequent pregnancies. Rho(D) immune globulin (RhoGAM) supplies passive anti‑D IgG that “mops up” fetal cells before the mother’s adaptive immune system can recognise the D antigen. The strategy is simple yet time‑critical: give the correct dose by the correct route as soon as possible after any sensitizing event, and repeat at the scheduled 28‑week antenatal checkpoint and after delivery of an Rh‑positive infant. This prophylaxis eliminates virtually all cases of severe HDFN that would otherwise require intra‑uterine transfusion or result in hydrops fetalis.