What should you know about human anti-D immunoglobulin?

During pregnancy or birth, small amounts of fetal blood can sometimes enter the pregnant person's bloodstream. If the pregnant person is RhD negative and the fetus is RhD positive, the immune system may recognise the RhD marker and make antibodies. This is called sensitisation. In a later pregnancy, those antibodies can cross the placenta and affect an RhD-positive fetus.

Anti-D immunoglobulin contains ready-made antibodies that remove RhD-positive cells before the immune system is likely to make its own lasting response. It is offered according to blood-group testing, pregnancy stage, local guidance and events such as bleeding, abdominal injury, miscarriage or procedures.

Attend recommended blood-group and antibody testing, and tell your maternity team promptly about bleeding, a fall, abdominal impact or a pregnancy procedure. Ask whether you need the Anti-D Injection and when it should be given. Keep a record of the dose and date, and tell clinicians if you have previously been sensitised or have an antibody result.

Contact your maternity team urgently after vaginal bleeding, abdominal trauma, significant pain, reduced fetal movement later in pregnancy or fluid leakage, even if you feel well. Seek emergency help for heavy bleeding, severe pain, fainting or feeling seriously unwell. Do not wait for a routine appointment after a possible sensitising event.

Ask whether your blood group is RhD negative, whether antibody screening shows sensitisation, which events require treatment, and the recommended timing. Ask what side effects to expect and whether anti-D remains useful if bleeding or an injury has already happened.