Anti-D immunoglobulin is a medication used to prevent Rh-D isoimmunization in Rh-negative women by stopping their bodies from developing antibodies against Rh-positive blood cells. It is given to an Rh-negative mother during and after pregnancy if her baby is Rh-positive to prevent hemolytic disease of the newborn. This injection works by neutralizing any RhD-positive antigens from the baby that may have entered the mother's bloodstream, which is why it is also given after events like miscarriage, ectopic pregnancy, or abdominal trauma