Rh Incompatibility Frequency and Treatment

Rh IncompatibilitySometimes the blood group of a mother and a blood group of a fetus Rh incompatible, i.e. they do not match. Disorders occur only when the mother is Rh negative, and the fetus Rh positive (inherited from the father).

Whenever a child is born – and sometimes even after spontaneous abortion, induced abortion or bleeding (see bleeding during pregnancy) – a part of the fetus’s blood passes into the mother’s bloodstream. Most Rh negative women deliver their first child without any difficulties, but after the childbirth they may become ”sensitive” to Rh positive blood, and in subsequent pregnancy the antibodies can move from her bloodstream to the bloodstream of the fetus and start destroying its red blood cells. This will not be the case if the blood group of the father is incompatible with the blood group of the mother.


About 85% of people are Rh positive. This means that Rh negative woman, in 85% of cases, will have a baby with Rh positive male. However, antibodies – as it seems – develop after the first pregnancy only at 5% of Rh negative women. However, in these cases, problems rarely occur thanks to modern methods of diagnosis and treatment.


Rh incompatibility does not cause any symptoms in mother. However, there is a danger that the baby will have hemolytic anemia and neonatal jaundice after delivery, or may be born dead. Dangers are considerably increased with each of the following Rh incompatible pregnancies.

What to do?

In the beginning of pregnancy, an automatic blood test is performed to determine – among other things – whether the pregnant woman is Rh negative or Rh positive. If you are Rh negative, your partner’s blood will also be examined and if the results show that the fetus will be Rh positive, your blood will be regularly checked throughout your pregnancy.

If it is your first pregnancy, the tests will first try to determine whether you are one of those rare cases in which antibodies develop before delivery. If you have been pregnant before, it is important to ascertain whether the treatment was effective during the previous pregnancies. If you have been pregnant for the first time before the medicine started using these modern treatment methods, it is quite possible that antibodies have already developed and blood tests will show their concentration in your body.


Thanks to the anti-D serum, the risk of Rh incompatibility has largely been eliminated today. Serum is given by injection to a mother shortly after each childbirth (as well as after abortion or bleeding), and it destroys red blood cells of the fetus in mother’s bloodstream before the mother’s body begins to produce antibodies. In rare cases where antibodies still develop, the so-called intrauterine transfusion may be used.