Blood group is one of the important things you should know about you and your child. It is much easier now, as it is documented well in the child's health booklet. However, even though it is there, many moms are not aware of it. I have talked to a few parents who think that the blood group of a child has to be a combination of the blood groups of the parents. It may not be so.
On the other spectrum are fathers who think that a different blood group is a ground enough to suspect that the child is not his. I once had an irate father demanding a paternity test just because his blood group was B and his child was A. From what he remembered, it was not possible. I had to draw out a chart in order to convince him otherwise!
Well, it is quite possible for the child to have a different blood group, and the answer lies in Genetics. So, for those who may not remember Mendel's law of inheritance and its application to blood groups, here is a refresher guide.
Blood groups
My blood group is O Rh Positive. It is a combination of two most important systems of blood group classification - the ABO system and the Rh system.
In 1900, an Austrian scientist, Karl Landsteiner wondered why some blood transfusions were successful while others led to even deaths of the recipients. Based on the research conducted by him, we now have the ABO system of blood groups. According to this, there are 4 possible types of blood groups, A, B, O, and AB.
Some 40 years later, the Rh system was recognized as an important system of classifying blood. One of the reasons was because a few children suffered from a severe disease of the blood - hemolytic disease of the newborn. After the discovery of the Rhesus (Rh) factor, the neonatal condition could be explained and today, preventive steps can be taken to prevent it. For all practical purposes, the Rh factor can be positive or negative.
Thus, we are left with 8 main types of blood groups - the RH positives and negatives of A, B, AB, and O.
So, what is your child's blood group?
The ABO blood group is expressed by a gene present on the chromosome number 9. We all know that we have two pairs of chromosomes - the one we received from the mother, and the other one from the father. Thus, we have two sets of these genes. So, how do these genes act when it comes to the blood group?
The genes are generally dominant or recessive. A dominant gene would be expressed even if it is alone, but a recessive gene would be expressed only in the absence of a dominant gene. The gene that expresses as A and B are dominant, whereas the one that expresses as O is a recessive gene.
So, if a person's blood group is A, he might have 2 dominant 'A' genes, or one dominant 'A' and one recessive gene for blood group 'O'. Consequently, when this person has a child, he might pass on the dominant 'A' gene or the recessive gene for blood group 'O' to him/her.
Here is a simple table for the possible blood group combinations for the ABO system. Just by looking at it, you can see that the child's blood group can vary a lot from yours! In fact, if your blood group is A and your partner's, B, your child's blood group can technically have A, B, AB, or O!
Similarly, with the Rh system, there are three factors, C, D, and E, out of which D is the most important. There is no recessive gene corresponding to D.
Why bother knowing your child's blood group?
Leaving the paternity issue aside, this is a valid question! Why bother knowing these complex things when you will know the child's blood group ultimately? Well, it is important to know your blood group, especially if you, the mom-to-be, are Rh negative.
If you are Rh negative, and you are planning to have a baby with a person who is Rh positive, there is a 50 to 100% chance that the baby will be Rh Positive. Your child is at the risk of suffering from hemolytic disease of the newborn.
It is a condition where the antibodies against the Rh factor from the mother end up attacking the developing fetus. The severity ranges from a mild condition to even death. So, you need to be aware of the blood groups before you start planning the baby.
What to do if you are Rh Negative?
If you are Rh negative and are planning to have a baby with a Rh positive person, the odds of the baby being Rh positive are quite high. Your first delivery might be uneventful, but during the delivery, there is a possibility of you being exposed to the child's blood. This will lead to the development of Anti-Rh Antibodies in your blood.
These antibodies are really tiny - they can cross the placenta and enter the foetal blood circulation. So, if your next baby is a Rh positive baby as well, these antibodies will end up attacking the poor fetus. But, this can be avoided.
So, when you are pregnant, your doctor will advise you to undergo a RhIG prophylaxis. In this, Rho(D) immune globulin, an injection to suppress the antibody production in the mother is given during and after pregnancy. This small step can prevent catestrophic events during the pregnancy.
Don't we all want our babies to be born safe and sound? If you don't know your blood group, please get it checked before you decide to have a baby.
Also read: These health problems may be linked to your blood type
Republished with permission from theAsianParent Singapore