Rh incompatibility in pregnancy

Rh incompatibility in pregnancy

Rh incompatibility is a phenomenon that worries a lot of future moms. Most people have the Rh factor in blood composition, but there is also a category of people born without this element in the blood group. In case the mother falls into the second situation, and the baby in the first, the pregnancy is considered to be at risk.
If a Rh-negative woman (without antigen D in the blood) has been exposed to Rh-positive blood (in a previous pregnancy, caesarean section, or abortion), her body may develop antibodies that attack Rh-positive blood. Therefore, the second pregnancy of a woman with Rh negative makes it possible to mix the blood of the mother with that of the fetus. In this situation, Rh incompatibility can cause various problems, from a normal neonatal jaundice to the death of the fetus in the womb.

What does Rh factor incompatibility mean?


The Rh factor is, in simple terms, a protein located on the surface of red blood cells. People who have this antigen (85% of the population) have Rh positive blood, and those without the Rh factor are called Rh negative.
If the baby takes on the blood group and the Rh factor of the father (positive) and the mother on the second pregnancy has Rh negative, her immune system will identify the red blood cells (the red blood cells) and consider them a foreign body. As a result, the mother's antibodies will attack the baby's blood cells.
The contact between the mother's blood and Rh positive blood can also occur during a transfusion, an ectopic pregnancy or pregnancy interruption, as well as during specific analyzes (amniocentesis).

The risk of Rh factor incompatibility

Rh factor incompatibility is possible only if the mother has Rh negative blood and the Rh positive father. The fetus may suffer if it inherits the blood composition of the father (Rh positive). Otherwise, any danger emerges from the discussion.
However, the chances of the baby having a Rh negative factor, like that of the mother, are only 30%. Therefore, the risk of Rh factor incompatibility is very high (70%).
Therefore, the determination of the blood group (in the ABO and Rh system) in the mother is mandatory during the prenatal period, since the first medical visit since the beginning of pregnancy.
Rh incompatibility never occurs in the following situations:

  • Rh mother positive and father Rh positive (child will have 100% Rh positive);
  • Rh mother negative and Rh father negative (child will have 100% Rh negative);
  • Rh mother positive and Rh father negative (the child will have Rh positive or negative, but the mother's body will not develop anti Rh antibodies);

Treatment of Rh factor incompatibility

Future mothers with a Rh negative blood factor will undergo a test to detect the existence of anti Rh antibodies in the body. Fortunately, the level of anti-Rh antibodies can be dosed so that the threat can be assessed.
The prevention and control of these antibodies is achieved by administering an immunoglobulin injection during the 28th week of pregnancy.
In order not to develop anti-Rh antibodies, treatment with immunoglobulins (gamaglobulins) can be given after birth, if the newborn is found to be Rh positive.
The immunoglobulin vaccine is given intramuscularly and does not cause significant adverse effects, regardless of whether the baby is Rh positive or Rh negative.
Immunoglobulins will attack Rh positive red blood cells that appear in the blood, acting as antibodies that the mother's body would produce, but because their numbers are much smaller, they will not affect pregnancy.
If the presence of anti-Rh antibodies is identified, administration of the immunoglobulin injection is no longer effective. In this situation the task will be monitored further. In the worst case, the baby will need a transfusion or intrauterine life (the chance of survival being at least 80%) or immediately after birth.
Careful medical observation, proper pregnancy monitoring, and the evolution of medical treatment means are three precious weapons that help moms around the world not worry too much about Rh factor incompatibility when they bring a baby into the world.