Rhesus factor and its role in pregnancy: important information for expectant mothers

Rhesus factor (denoted as Rh) is a special protein present on the surface of red blood cells in Rhesus-positive people. This protein was discovered in the blood of rhesus monkeys, hence its name. Rhesus factor can act as an antigen, causing the formation of antibodies (immunoglobulins G) in Rhesus-negative individuals. The second name for the Rh factor is the D antigen.

Worldwide, about 85% of people are Rh positive, while the remaining 15% are Rh negative.

Rh factor determination is usually done at the same time as blood type determination. The presence or absence of Rh factor in your blood does not affect your ability to get pregnant. However, if a woman is Rh-negative and the pregnancy is Rh-positive, it can lead to a serious complication - hemolytic disease in newborns.

Why does a Rh conflict occur?

If a woman has Rh-negative blood, and the future father of the child has Rh-positive blood, this does not pose a danger. Problems arise only when a Rh-negative woman conceives a child with a Rh-positive man. In such a situation, the baby may inherit the Rh positive factor from the father and his blood may contain Rh factor, which is formed in the fetus' body at 8 weeks of pregnancy.

When fetal red blood cells with Rh factor enter the mother's blood, the mother's immune system begins to produce antibodies to destroy them. Some of these antibodies can pass through the placenta back to the fetus and cause its red blood cells to stick together and break down. This leads to hemolytic disease, which can have serious consequences.

How does hemolytic disease manifest itself?

Hemolytic disease results in the destruction of red blood cells, which reduces the number of these cells, causes anemia, and leads to increased levels of brain-toxic bilirubin in the blood. The liver and spleen may also become enlarged, impairing their functions. The fetus may develop tissue swelling, which is considered a serious manifestation of the disease. The baby may be born prematurely, jaundiced and with anemia. In some cases, hemolytic disease can lead to stillbirth.

Is there any cause for concern?

Fortunately, severe forms of hemolytic disease are rare. Modern medicine provides methods to prevent serious complications related to Rh factor and pregnancy. There are drugs called anti-rhesus immunoglobulins that can prevent antibodies from forming in the mother's body. Methods have also been developed to manage Rh-positive pregnancies in Rh-negative women.

What should be done?

To avoid hemolytic disease, you should seek timely counseling and carefully monitor your pregnancy. It is important to inform your doctor about past pregnancies, miscarriages or abortions, especially if they are associated with Rh conflict. Your Rh antibody level should be determined at 8 weeks of pregnancy and then checked regularly every month until 32 weeks of pregnancy. From 32 to 35 weeks, this level should be monitored twice a month and then every week until delivery.

Your doctor will monitor your condition and prescribe anti-rhesus immunoglobulin injections if necessary. This drug helps to destroy the Rh factor quickly, preventing the formation of antibodies in the mother's body. The drug should also be used after childbirth. Anti-Rhesus immunoglobulins are also recommended for abortion, ectopic pregnancy or miscarriage in Rh-negative women.

It is important to follow all of your doctor's recommendations. A healthy baby will be your reward for all your efforts. May your pregnancy go smoothly and your baby be born strong and healthy!