Synonyms
Rhesus incompatibility, blood group incompatibility English: blood group incompatibility
Definition
A blood group incompatibility in pregnancy between mother and child occurs when the child has characteristics on its red blood cells (erythrocytes) that the mother does not have on hers. Most often this happens through the so-called rhesus feature. The constellation mother rhesus negative and fetus (unborn child) rhesus positive causes the mother to produce antibodies (S. immune system) against the child’s red blood cells.
However, this only happens when maternal and fetal blood have come into direct contact with each other. This contact occurs with every birth (including miscarriage and premature birth), when an extrauterine pregnancy is corrected (see above) and when the placenta is prematurely detached. In the fetus this process leads to water retention in the tissue and abdominal dropsy.
Swelling of the liver, heart and placenta is also possible (Hydrops fetalis). In the newborn, an increase in red blood cells (erythroblastosis fetalis) and massive jaundice can then be observed. If there is any uncertainty, the diagnosis can be made by examining the maternal blood or the blood of the umbilical vein for antibodies.
If a low level of red blood pigment is detected in the foetus, a blood transfusion should be carried out in the womb. In general, an early delivery should be aimed for so that the foetus is not further exposed to the maternal antibodies. If the blood values remain poor even after this, a blood exchange transfusion with Rhesus-negative blood, which the antibodies cannot harm, is carried out.
Furthermore, there is a blood group incompatibility with regard to the characteristic AB0, although this occurs less frequently. Only the antibodies of female carriers of blood group 0 can pass through the placenta and thus lead to complications. But even these are milder, as the antibodies are only formed at a late stage of pregnancy. Jaundice is also treated with phototherapy (light therapy) above a certain limit.
