About the Rh factor in pregnancy – one of the most important blood tests at the beginning of a pregnancy regards the Rh factor. What is it about? You are tested to see if you have a positive or a negative Rh factor – most people have a positive one (over 80%).
Each person has a certain blood type: A, B, AB, O, while each person in each blood type can have a positive or negative Rh. The Rh factor is extremely important in the evolution of pregnancy – it mainly refers to a protein that can be found (positive Rh) or not (negative Rh) in blood red cells. The Rh factor will not have any effects on you directly, but is essential for your pregnancy.
About the Rh factor in pregnancy:
The initial blood test aims at finding out if you have a positive or a negative Rh factor – how important is that? Everything is about compatibility: if it is negative, but the baby’s father-to-be has a positive Rh, there is an incompatibility which poses risks for the pregnancy. On the other hand, if you both have are Rh positive, Rh negative or if the mother is positive and the father is negative one, you do not have anything to worry about.
When the two partners have incompatible Rh factors, there is the risk of incompatibility between the mother and child: if the father is Rh positive and the mother negative, the child might have a positive Rh factor, like the father (this happens in most cases; however, if the child will have a negative Rh, there are no risks). What does this mean exactly and what are the involved risks?
Rh factor in pregnancy – the Rh incompatibility between mother and child:
The baby’s blood might have a positive Rh, like the father’s, so when his blood enters the mother’s blood circulatory system, her body will not recognize the proteins that are characteristic to positive Rh (negative Rh implies the lack of such proteins) and, thus, it will treat them like dangerous foreign bodies; therefore, it will generate antibodies to fight them; these antibodies will go into the baby’s circulatory system, where they will attack the red cells from the baby’s blood and destroy them. As a consequence, the newborn can have a hemolytic disease, which involves risks concerning jaundice, severe anaemia, damage on the foetus’ organs (heart, brain, liver, lungs) and even the newborn’s death (when the red cells are severely affected).
However, the risk does not appear during the first pregnancy, but during the ones that follow: in a normal pregnancy, the mother’s and child’s blood systems are separated and the child’s blood does not go into the mother’s circulatory system. Therefore, the risk is higher during the second, third etc. pregnancy, because, during labour, the foetus’ blood can mix with the mother’s blood; in this case, the mother’s body, by not identifying the proteins in the foetus’ red cells, creates antibodies, which, during the next pregnancy, will enter the foetus’ red cells and attack them – as it was previously mentioned, there are several risks regarding the foetus’ development. The risk is as high during the first pregnancy as during the following ones if the contact between the foetus’ and mother’s blood is made in other ways: ectopic pregnancy, miscarriage, amniocentesis, or if the mother was given a positive Rh blood transfusion (antibodies that will attack the positive Rh proteins during the next pregnancy are created).
Rh factor in pregnancy – measures:
Immunoglobulin. The blood test regarding the Rh factor that verifies the compatibility is thus extremely important. When there is the risk of incompatibility between the mother and foetus, the doctor will administer immunoglobulin (RhIg), which is injected to the mother around week 28, in order to prevent any risks, and again after giving birth, in order to avoid the creation of Rh antibodies that could affect a possible pregnancy in the future. This prevents risks and does not imply dangerous side effects. Immunoglobulin is also used as treatment if a woman with negative Rh has been in situation that could cause the creation of antibodies: miscarriage, abortion, ectopic pregnancy, blood transfusions after amniocentesis.
Another test will be made in order to verify the existence of antibodies – if the mother already has anti-Rh antibodies, her pregnancy will be constantly monitored in order to check the antibodies level. Doctors will closely verify the foetus’ state – some babies are not affected by the hemolytic disease, but they do, however, have trouble during their development. When there is a high risk, doctors can administer a blood transfusion in order to stabilize the foetus’ red cells level and avoid further risks. Fortunately, medical tests and immunoglobulin treatments lead to a low risk in the development of the hemolytic disease.