Rh Immune Globulin

An RhD-negative pregnant person can be exposed to fetal RhD-positive red blood cells without feeling ill or having an obvious clinical sign. That exposure can prime the immune system to make anti-D antibodies, which may cross the placenta in a later RhD-positive pregnancy and destroy fetal red blood cells. Rh immune globulin (RhIG) interrupts that process. It supplies temporary, passive anti-D protection before maternal immune memory develops. The clinical decision is therefore preventive and time-sensitive: confirm that the person is RhD-negative and not already sensitized, identify whether an exposure could have occurred, and match the product, dose, route, and timing to the situation.