Blood groups are composed by 2 components – major (the kind that you already know about – i.e A, B, AB and O) and the Rh (based on the presence or absence of D – Antigen). With Rh, an individual can be classified as Rh positive or Rh negative. The Rh – negative blood type can pose risks during pregnancy, including increasing the risk of miscarriage or stillbirth in the second or third trimester.
WHAT IS Rh FACTOR?
Rh or Rhesus factor is a protein present on the red blood cells. Rh factor is governed by genetics. 90% of the people all over the world are Rh positive. Some people lack the Rh (D) protein and they are referred to as Rh Negative. Being Rh Negative doesn’t harm their quality of life in any ways, however sometimes it can play a role in influencing miscarriage.
WHAT IS Rh FACTOR SENSITIZATION?
Rh factor sensitization is a phenomenon that occurs when you and your baby’s blood being of opposite Rh factor result in a chemical reaction. There are no problems if:
- The mother has the Rh Factor (Rh positive)
- Neither parent has the Rh factor (both are Rh negative)
However, if you are Rh negative and the father is Rh positive, there is a possibility that the baby’s blood may also be Rh positive (the opposite of yours). In this case, your body may manufacture a substance called Rh antibody that can affect your unborn baby’s blood cells. Normally antibodies are useful in defending the body by fighting against various microbes and diseases. But in this condition, this can be harmful to your baby and potentially lead to pregnancy loss.
WHAT IS THE LINK BETWEEN Rh SENSITIZATION AND MISCARRIAGE?
Being Rh negative does not mean that you will necessarily have a miscarriage. It simply means that you carry a risk of being sensitized if your blood reacts with your baby’s. This risk can be reduced significantly by administering Anti – D (Rho GAM) injection to the lady after a previous pregnancy loss, ectopic pregnancy or abortion.
Even if you haven’t had any prior losses, its important to get yourself checked for the Rh(D) antibody.
WHAT ARE THE RISKS OF BEING AN Rh-NEGATIVE MOTHER WITH Rh POSITIVE FETUS?
The mother’s blood does not normally mix with the baby’s blood during the pregnancy unless there has been a procedure (such as Chorionic Villus Sampling, Amniocentesis etc). However, during delivery there will be minute tears leading to mixing of fetal blood with the mother. This is normal and for most women not a problem. However, an Rh-Negative mother will develop antibodies to attack the Rh-Positive blood. First pregnancy is uneventful and takes place without any problems. But if the same women become pregnant for the second time and if that baby is Rh positive, the antibodies formed earlier crosses the placenta and attacks the baby’s blood cells resulting in Hemolytic Disease of Newborn (HDN). This may mean that the baby has anemia, jaundice, become brain damaged or even die before it can be born (still birth).
The chance of forming Rh antibodies occurs with each pregnancy, including ectopic pregnancies (when the fertilized egg implants itself outside the uterus) and pregnancies that end in miscarriage or termination.
HOW CAN HEMOLYTIC DISEASE OF NEWBORN (HDN) BE PREVENTED?
Hemolytic disease can be prevented in women who are not already sensitized. Fortunately, an injection can be given which stops a Rh-negative mother from producing the antibodies that attack the Rh-positive blood of the fetus. This is known as the Anti – D injection or RhoGAM injection and contains anti – D immunoglobulin. This injection has to be given within 72 hours of delivery to Rh negative mothers. This should also be given to Rh negative women after miscarriage, vaginal bleeding, ectopic pregnancy. In case of any doubts, anti – D antibody levels/titres in the blood can be checked periodically during the pregnancy. Depending on your antibody levels, you may require specialist care and your fetus may require transfusions before birth to prevent the baby being anemic.
CONCLUSION
If you have experienced Rh sensitization in previous pregnancies, you still have plenty of hope in carrying future pregnancies to term. If you have questions about the Rh factor or whether or not you are in this group of women, please be free to contact our experts.
