What is anti-D immunoglobulin used for?

If your blood is Rh-negative and the baby’s blood is Rh-positive, a small amount of fetal blood can sometimes enter your bloodstream during pregnancy, birth, bleeding, injury, or a procedure. Your immune system may treat those cells as unfamiliar and make anti-D antibodies. Anti-D immunoglobulin supplies temporary protection that helps clear Rh-positive cells before this immune response develops. It does not change your blood type and does not treat antibodies that have already formed.

Your maternity team can check your blood group and antibody status, then explain whether anti-D is advised and when it should be given. Tell them promptly about vaginal bleeding, abdominal injury, pregnancy loss, or any procedure during pregnancy. Keep a record of your blood group and any injection you receive. For a fuller explanation, see Anti-D Immunoglobulin and Anti-D Injection.

Contact your maternity service promptly after bleeding, a fall or blow to the abdomen, or a pregnancy-related procedure, because timing can affect the plan. Seek urgent assessment for heavy bleeding, severe abdominal pain, fainting, or reduced fetal movement. These symptoms need evaluation even if you have already received anti-D.

Ask whether you are Rh-negative, whether your antibody screen is clear, which events could require anti-D, and what symptoms should prompt an immediate call. You can also ask how the injection is given and whether another dose may be needed after birth or an event that could mix blood.