Overview
Why Rh(D) Status Matters in Pregnancy
An Rh negative blood type is not an illness. The clinical risk appears when an Rh negative pregnant patient is exposed to Rh positive fetal red blood cells.
An Rh-negative blood type is not an illness. The clinical risk appears when an Rh-negative pregnant patient is exposed to Rh-positive fetal red blood cells. That exposure can occur with delivery, bleeding, trauma, pregnancy loss, or an invasive procedure. If the immune system forms anti-D antibodies, those IgG antibodies can cross the placenta in a later Rh-positive pregnancy and destroy fetal red blood cells. Rh(D) immune globulin (RhIG) prevents that immune memory; it cannot reverse antibodies that have already formed.