There are many questions that readers make about the inheritance of baby Rh factor. We will try to explain in a simple way how the Rh factor of the baby is composed, in what cases it will be positive and in which negative
There are four types of blood or blood groups: O, A, B and AB. Regardless of the type of blood, all people have a positive or negative Rh factor depending on the characteristics of their blood.
Rh is determined by an antigen. When a person's blood has a protein (D antigen) on the surface of red blood cells, its Rh factor will be positive, when this protein is not present its Rh factor will be negative. Most people (85%) are Rh positive.
The baby can inherit the blood group and factor of one of his parents or a combination of both as shown in the table above.
Rh's inheritance It consists of two genes, one is inherited from the mother and the other from the father and follows a common pattern. The Rh positive gene is dominant, that is, even when combined with a Rh negative gene, the positive one prevails.
If a person has the genes + +, the Rh factor in the baby's blood will be positive.
If a person has the genes + - , the Rh factor in the baby's blood will be positive.
If a person has the genes - - , the Rh factor in the baby's blood will be negative.
Probability Chart
I tell you my own experience that is significant as an example. Both my husband and I are positive Rh Factor, but we are both + -, that is we are positive because the positive is dominant but we both have a father with a negative Rh factor (we are the case 6). Two of our daughters are Rh Factor positive and one is Rh Factor negative.
However, about Rh incompatibility or Rh sensitization, this can only occur when the mother is Rh negative factor and the Rh positive father (cases 4 and 7). If the baby inherits the Rh positive factor from the father, hemolytic disease of the newborn occurs. The mother's immune system can "attack" the Rh-positive red blood cells of the fetus causing anemia, jaundice and even fetal death. We have already detailed all this extensively when we explained what Rh incompatibility is.
