​What is a rhesus blood type?

There are two different rhesus bloodtypes: rhesus positive and rhesus negative. 15% of people are rhesus negative. The rhesus bloodtype is hereditary.

Can it cause a problem?

If you are expecting a RhD (rhesus) positive baby – approx. 60% of women do – you might get immunized. This happens when the baby’s RhD positive blood mixes with the mothers RhD negative blood. If you get immunized your body will produce so called antibodies which cause anaemia or other serious illness in the unborn and/or newborn baby. If it happens there are good options for treatment, but it may be necessary to induce labour to prevent further anaemia. There are approx. 10 serious cases of serious illness a year in Denmark and we would like to reduce this number further.

What can be done?

In pregnancy it is possible to determine the RhD type of the unborn baby by taking a bloodsample from the mother. Your own doctor (GP) has to do this. If you baby, like you, is RhD negative no further action needs to be taken. If your baby is RhD positive you will be offered an injection of anti-D immunoglobulin when you are approx 29 weeks pregnant. When you see your midwife at 28 weeks gestation she will check the result of the blood test and give you an appointment. You will get the injection here. We may also offer the injection to you at other times during you pregnancy, for example if you have episodes of heavy bleeding or experience trauma to the abdomen.​

After the birth

After you have given birth and your baby is RhD postive, you need another injection af anti-D immunoglobulin. The injection should preferably be given within 48 hours but can be given up to 72 hours postnatally.

About Anti-D

Anti-D is human immunoglobulin IgG anti-D (antibodies). It is created using palsma from women who have been rhesusimmunized. The injected antibodies attatch themselves to the red blood cells from the baby’s blood (which may be present in the mothers blood) and breaks them down. Subsequently, the body will not create any antibodies itself. Treatment with anti-D prevents most but not all cases of rhesusimmunization Patients rarely have any side effects of anti-D, but very rarely the injection can cause a severe allergic reaction. The baby is not affected by the antibodies.