If a BPAS doctor or nurse has told you that your blood group is Rhesus-negative we recommend that you have an anti-D immunoglobulin injection.
As well as the main blood groups (A, B, AB or O) there is a second factor called Rhesus. People who are Rhesus-positive have a substance called D-antigen on their red blood cells. People who are Rhesus-negative do not have the D-antigen on their red blood cells.
Whether someone is Rhesus-positive or negative is inherited from both parents. If the father of the pregnancy is Rhesus-positive then there is a chance that the fetus will also be Rhesus-positive even if you are Rhesus-negative.
If at any stage of pregnancy there is mixing of your Rhesus-negative blood with that of the fetus who may be Rhesus-positive, your body’s defence mechanism, called the immune system, may form antibodies against the D-antigen. These 'anti-D' antibodies attack red blood cells with the D-antigen on them.
This mixing of blood can happen at various stages of pregnancy, including abortion and this will be potentially harmful to any babies you have in future that are Rhesus-positive because the antibodies stay in your system.
What does the anti-D injection do?
It will 'mop up' any D-antigen that may have been carried across from the fetus to your blood supply at the time of the abortion. The idea is to neutralise the D-antigen from the fetus before it has time to cause your body to produce its own natural anti-D antibodies.
What might happen if I don’t have the anti-D injection?
If you do not have the anti-D injection, it is possible that you will produce anti-D antibodies. If you become pregnant again and the baby is Rhesus-positive the anti-D antibodies might enter the baby’s circulation and attack its blood. If this were to happen it would make the baby ill, either in the womb or after it is born. This is called Haemolytic Disease of the Newborn, which is a very serious condition.
Do I have to have the anti-D injection?
Ultimately, it is your decision whether or not to have the injection. However, it is strongly recommended that you do.
Is it safe?
Anti-D injections have been in use for over 40 years and there are no known serious side effects. At worst, some women experience short-term rashes or flu-like symptoms, but these are very uncommon.
All Rhesus-negative women having an abortion are offered an anti-D injection, irrespective of whether the fetus or their partner is Rhesus-positive or negative.