In 5-10% of all births, there is Rh antigen incompatibility between the couples, which is known as blood incompatibility. Now we consider blood incompatibility and what benefits we have in childbirth.
What is blood incompatibility or Rh incompatibility?
If the woman is Rh negative and her partner is Rh positive, then there is Rh incompatibility (blood incompatibility).
What is the Rh antigen?
Rh antigen is a protein located on red blood cells (erythrocytes). Most people carry this antigen, these are Rh positive people. Those who do not carry the Rh antigen in their blood cells become Rh negative, of which 15% of women are Rh negative. It says on your blood group cards that you are Rh positive or Rh negative.
If there is Rh incompatibility between couples, is there any harm in pregnancy?
When the mother becomes pregnant, her baby in the womb is 50% Rh positive. If the baby is Rh positive, the blood cells passed from the baby to the mother as the pregnancy progresses cause the mother’s transport system and antibody formation due to the Rh antigen. And when the mother is pregnant once again, if her baby is Rh positive again, then the antibodies that were formed during the previous pregnancy will pass through the placenta to the baby in this new pregnancy. It breaks down the baby’s blood cells and causes anemia (anemia) in the baby. After a while, edema starts to accumulate in the 3rd spaces of the baby , which we call this situation ‘hydrops’ in medical language. If the event continues, it will cause death in the womb due to antibodies related to blood incompatibility.
So, can we say that it does not cause problems in the first pregnancy for couples with blood incompatibility?
Yes. Usually there is no problem in the first pregnancy. Blood incompatibility is a condition that has the risk of causing problems in subsequent pregnancies.
What should be done so that blood incompatibility does not risk subsequent pregnancies?
If the mother is Rh-negative and the father is Rh-positive, that is, there is blood incompatibility, some precautions to be taken when the woman is pregnant prevent blood incompatibility from risking subsequent pregnancies. What are these measures?:
1- If the result is negative after examining the indirect Coombs test in the mother at the 28th week of pregnancy, an anti-D immunoglobulin injection is given to the mother. This is an injection made from the buttock and a single dose is sufficient.
2- After birth, the baby’s blood group is determined. If the baby is Rh positive like his father, then the mother is given a repeat injection. . if the baby is Rh negative, then there is no need for an injection.
3- A blood incompatibility injection is given to the mother in every case when the mother has bleeding while she is pregnant. In addition, if interventions such as amniocentesis were performed in Rh-negative pregnants, an anti-D immunoglobulin injection should be performed.
What is the indirect coombs test?
The indirect Coombs test is a test that detects whether the mother has antibodies against the Rh antigen in her blood. If the result is negative, it means the mother has no antibodies, which is good. If the result is positive, it means that the mother has antibodies, these antibodies can cross the placenta and lyse the baby’s blood cells. Therefore, when the indirect Coombs test is positive, we repeat the test every 4 weeks to determine the antibody level. We follow up with ultrasound whether anemia develops in the baby.
We investigate the indirect coombs test before the anti-D immunoglobulin injection at 28 weeks in pregnant women whose spouse is Rh-positive. If the test is negative, it means that the mother is not sensitized, which is our expectation. In this case, we give the mother a protective blood incompatibility injection. If the test is positive, that is, if the mother is sensitized and has antibodies, then there is no point in giving a blood incompatibility injection and we will not do it.