How Can Negative Rh Factor Affect Your Pregnancy?
If you're planning to get pregnant, it's important that you know your blood type (A, B, AB, O) and Rh (Rhesus) factor (Rh+, Rh-), since it may have a significant influence on your pregnancy and your baby's health. And if your Rh-negative it's also important that you know what is the Rh factor of your baby's father.
What is the Rh Factor and Why is That Important?
The Rh factor is an inherited antigen often present on the surface of red blood cells. It is named after a type of monkey in which was first found. If you have this antigen, your blood type is positive (Rh+), and if you don't have it, your blood type is negative (Rh-). The Rh-positive is the most common blood type.
Even though it's not a disease and it won't affect your overall health, it might affect your pregnancy. If your baby's father is Rh-positive, you should pay special attention once you get pregnant.
How is the Rh Factor Inherited?
A child inherits the Rh factor from its parents. It is inherited independently of the ABO blood type alleles. If both parents are Rh-negative the child will be Rh-negative as well, but if both parents are Rh-positive the child could either be Rh-positive or Rh-negative. This also happens if one parent is Rh-negative and the other one is Rh-positive.
What is the Rh Incompatibility?
The Rh incompatibility occurs when a mother is Rh-negative and a baby is Rh-positive because mom's red blood cells don't match up with baby's. This may cause some problems during the pregnancy. Probably not in the first one, but the chances are higher in the later ones.
What is the Rh Sensitization?
Rh sensitization can occur when a person with Rh-negative blood is exposed to Rh-positive blood. This causes the production of antibodies to attack "foreign" blood cells. A person with Rh-negative blood who makes antibodies is called Rh sensitized. This rarely happens in the first pregnancy, because the mother and the baby don't share blood systems. However, a small amount of blood can cross through the placenta from the fetus into the mother's blood system. This may happen during pregnancy or labor or if a Rh-negative woman has had any bleedings during the pregnancy or amniocentesis and CVS (Chorionic villus sampling). It's also possible to develop antibodies after a miscarriage, an ectopic pregnancy or after an induced abortion.
It's important that a mother gets preventive treatment during the first pregnancy so that if she later again becomes pregnant with the Rh-positive fetus, the baby won't be at risk of Rh disease. The Rh antibodies will destroy some of the baby's red blood cells, which causes hemolytic anemia. Red blood cells carry oxygen to all parts of the body, so without enough of them, the baby won't get enough oxygen, which can lead to serious illness. Severe hemolytic anemia may even be fatal to the fetus.
How can I Prevent Rh sensitization and What if I Have Already Been Rh Sensitized?
You could find out if you have already been Rh sensitized by doing a blood test, called an antibody screen. The test will show you if you have developed any antibodies to Rh-positive blood and how many antibodies have already been made. This test is performed during your first trimester and again during week 28 of pregnancy.
You can prevent the Rh sensitization if you receive a shot of Rh immunoglobulin (RhoGAM). But RhoGAM isn't helpful if you have already been Rh sensitized. RhoGAM should be given to the Rh-negative mother around the 28th week of pregnancy (to prevent Rh sensitization for the rest of the pregnancy) and within 72 hours (if it's possible within first 36 hours) after the delivery of a Rh-positive infant, after a miscarriage, abortion, or ectopic pregnancy and after amniocentesis or CVS or any other situation where baby's and mother's blood can mix. If baby's Rh negative, there's no need for a RhoGAM shot.
What if I am Rh Sensitized and My Baby is Rh-positive?
If you are Rh sensitized, you should check your baby's blood type. If its' negative - your compatible and there's no need to worry. But if it's positive, you should pay special attention to your baby's health during the pregnancy. If tests show that your baby has severe anemia, it might be needed to deliver your baby before 37 weeks of pregnancy or to give her blood transfusion while she's still in the uterus (this is performed through the umbilical cord). If the anemia is not severe, your baby may be delivered naturally, but maybe she'll need a blood transfusion to replace her blood cells.
