What is maternal-fetal Rh incompatibility and why does it occur?
Maternal-fetal Rh incompatibility develops when a pregnant woman has Rh-negative blood and the fetus has Rh-positive blood . But what exactly does that mean?
It's important to know that different blood types depend on proteins located on the surface of red blood cells. There is also another protein, the Rh protein. People who have this protein are Rh positive, and those who don't are Rh negative.
There is a 50% chance that:
- If a woman is Rh negative and becomes pregnant with an Rh positive male, the baby will also be Rh positive.
If this situation occurs, then we will be facing a case of maternal-fetal Rh incompatibility.
As explained by the Dr. Juan José Vidal Peláez, Director of the Women's Unit, to the portal infosalus.com, It is very rare for problems to occur during the first pregnancy except in the case of bleeding. This is because the fetus's blood is not in contact with the mother's blood until the placenta moves during childbirth.
What happens when there is maternal-fetal Rh incompatibility?
The mother's body will produce antibodies to fight the 'foreign substance' that Rh-positive fetal blood cells represent. The problem arises when these antibodies reach the fetus through the placenta. At this point, they will destroy the baby's red blood cells.
As these red blood cells break down, they produce bilirubin, which causes the fetus to develop a yellowish tint , or jaundice. The intensity of this jaundice depends on the amount of bilirubin produced.
In subsequent pregnancies, this process would be even more likely. This is because the antibodies would remain in the mother's blood and easily enter into contact with the fetus through the placental circulation.
Maternal-fetal Rh incompatibility: prevention, detection, and treatment
Prevention
When an Rh negative woman becomes pregnant:
- A blood test is performed, called Coombs test to check for the presence of these antibodies. Although harmless to the woman and the fetus, if the fetus is Rh negative, they can complicate the pregnancy. To prevent this, a dose of the anti-Rh vaccine around 28 weeks of gestation and another in the first 3 days after birth, even in the case of abortion.
- Likewise, if amniocentesis or a chorionic villus sampling is necessary during pregnancy to rule out genetic diseases, the vaccine must be administered after each of these tests.
Detection and treatment
Although in Western countries it is rare for women to be sensitized and have anti-Rh antibodies due to the use of these vaccinations, in cases where they do:
- During pregnancy you will have to monitor the levels of these antibodies throughout pregnancyIf they are increasing, the fetus will be extracted as soon as it is mature enough. If it is not, it will be necessary to perform intrauterine transfusions to the fetus until it reaches the desired maturity.
- After the birth of the baby, it will be necessary to perform one or more exchange transfusions to exchange the patient's blood for Rh-negative blood. This procedure will be performed until the anti-Rh antibodies transmitted by the mother completely disappear.
As Dr. Juan José Vidal Peláez states to this publication, thanks to the evolution of Prenatal Diagnosis , the complications related to maternal-fetal Rh incompatibility are practically overcome.
If you found this article interesting and would like to be seen by a specialist in Gynecology and Obstetrics, the Women's Unit at Ruber International Hospital has a specialized department in this area. You can request more information by calling 91 387 51 72/73/74 or schedule an in-person appointment with top specialists.