RHIncompatibility During Pregnancy
If RH incompatibility is not detected and treated during pregnancy, it will endanger the health of mothers and babies. Therefore, the blood groups and possible risks of the parents should be determined to take precautions before becoming pregnant.
It is known that there more than 100 blood groups determined by genetic characteristics, and universally accepted major blood groups are named by the ABO system. Each person has one of the main groups A, B, AB and 0. Blood groups are determined depending on the antigens on the surface of red blood cells. Antigens are proteins that stimulate the immune system. People with blood type A have only A antigens, and type B has only B antigens. While people with type AB have both antigens, people with type 0 have neither A nor B antigens. There are also other antigens that specialize in blood groups. The most important one is the RH factor. Those who have no Rh antigen in their blood are defined as Rh negative (-), those with RH antigen as Rh positive (+). More than 85% of people are Rh positive. RH incompatibility occurs especially when the mother is Rh (-), and the father is Rh (+).
Precautions During Pregnancy
The blood type of a mother should be known before birth. If the mother has a document that is not possible to express the blood group correctly, the test should be done again to determine her blood group. Knowing the blood type of mother is essential to take precautions against RH incompatibility. For example, when the mother is RH (-) and the father is RH (+), the baby, according to Mendel’s Laws, will be born 50% or 100% RH (+) depending on the father’s genetic structure (heterozygous or homozygous). It is known as “RH incompatibility” in any case when the mother is RH (-), and the father is RH (+), since it is not determined yet that how his genes were regulated in scientific research. It is very dangerous when a baby’s blood is mixed the mother’s blood even in a small amount if the baby is really RH (+). The immune system of the mother produces substances called antibodies against the baby’s red blood cells which are different from their own blood cells.
The mother’s antibodies begin to kill blood cells in the second pregnancy. The greater the amount of antibody passed, when the baby is in the womb, the higher the risk of anemia which causes heart failure and death. To protect both the mother and the baby, the only thing that needs to be done is being sure that stimulation does not occur at all, since the mother’s immune system constantly produces antibodies against foreign red blood cells after being stimulated.
RH Incompatibility also may occur because of wrong blood transfusion and improperly sterilized sterilization of surgical instruments or injections.
For this reason, each mother with Rh (-) should be tested in terms of anti-Rh antibodies at the beginning of pregnancy (Indirect Coombs test). Since the most important treatment of blood incompatibility is prevention, the following rules must be followed:
- Blood groups of parents should be identified at the beginning of pregnancy.
- If parents have Rh incompatibility, the Indirect Coombs test should be done at appropriate intervals.
- Women can be given a shot of Rh immune globulin during week 28 of their first pregnancy if necessary.
- If the baby’s blood type is Rh positive, Rh hyperimmune globulin should be given to mothers within 72 hours to prevent the production of antibodies to protect the next pregnancy.
- Levels of antibody in the blood are checked in the later months of pregnancy; the baby should be treated in a perinatology clinic with special tests.