Rh factor

Rh factor

Rh factor describes the compatibility between blood types involving and Rh blood groups. They play an important role in transfusion and obstetrics. Rh groups were discovered in 1940 by Karl Landsteiner and Alexander Wiener in experiments on Rhesus monkeys, from which the name was also preserved. 40 years ago, Karl Landsteiner identified the four blood groups A, B, AB and 0, a discovery that made the transfusion a safe way.

What is Rh factor?

Each person has one of four blood groups, and these are determined based on the antigens found in the blood cells. Antigens are proteins that are found on the surface of blood cells and can generate a response from the immune system.

The Rh factor is a protein found on the surface of a blood cell (red blood cell). 85% of the population has the Rh factor and they are said to be Rh positive, and those who do not have Rh are negative.

Rh positive or Rh negative?

It is important, especially if you want to have a baby, do blood tests to find out your blood group. If, the mother is Rh negative, and the father Rh positive, the fetus may inherit the father's Rh, except that problems may occur.

What happens to a Rh negative pregnancy?

If you are Rh negative, it is possible to develop antibodies in a Rh positive child. If a small amount of the baby's blood mixes with your blood, which happens frequently, your body will react as if you were allergic to the baby. This means that you have become sensitive, and the antibodies have crossed the placenta and attacked the baby's blood.
These can destroy the baby's red blood cells, causing anemia (the blood has a low blood redness). This disease is called hemolytic anemia. It is a severe complication of pregnancy because it can affect the brain or even cause the death of the fetus. Hemolytic anemia occurs if the mother with Rh negative:

  • She had a pregnancy loss

  • She had an abortion

  • He had an ectopic pregnancy

  • Blood transfusion


  • A blood test will inform you about the blood group and Rh factor.

  • A certain type of test that will tell you if you have Rh antibodies.

  • Rh immunoglobulin (RhIg) injections

When are Rh immunoglobulin injections used?

Rh immunoglobulin is used during and after pregnancy:

  • If a mother with Rh negative has not developed Rh antibodies, the doctor may suggest injecting Rh immunoglobulin in the 28th week of pregnancy to prevent anemia in the future pregnancy;

  • If the child is born with Rh negative, it is recommended that the mother take the injections to prevent Rh antibodies from developing;

  • Rh immunoglobulin treatment is required only for pregnancy. Each pregnancy and birth with Rh positive, requires repeated doses of Rh immunoglobulin.

  • Also, a woman with Rh negative will receive treatment after a loss of pregnancy, miscarriage or ectopic pregnancy to prevent the appearance of antiRh antibodies that could potentially attack a future pregnancy.

Other Reasons for Immunoglobulin Administration Rh

  • At the time and if amniocentesis occurs, the positive Rh of the fetus can be mixed with the negative Rh of the mother, producing antibodies, making Rh immunoglobulin necessary.

  • The mother's negative Rh may receive Rh immunoglobulin after birth, regardless of whether it uses sterilization, by tying the uterus, for the following reasons:
    - It is possible for this to change and decide to reverse the sterilization
    - There is a very small chance of failing sterilization o In the event of a future transfusion, treatment will help prevent the appearance of antibodies.

The appearance of antibodies

When a pregnant woman with Rh negative develops anti-Rh antibodies, Rh immunoglobulin treatment is no longer effective. In this case, the pregnancy will be held under specialized care to observe the development of the pregnancy.
It is possible for the baby to be born at term and immediately after birth he will be given healthy blood to replace the diseased cells. For more severe cases, the baby will be born prematurely and will be transfused with intrauterine life.

Rh factor negative

  • 15% of the population has Rh negative factor

  • The Rh factor does not affect a person's health

  • Problems may occur when a mother is Rh negative during pregnancy and the Rh child positive, but detected early can be prevented by the administration of Rh immunoglobulin.

Tags Blood groups RH negative Rh negative in pregnancy Rh factor Factor Compatibility rh parents