Your baby & your Blood group

by Admin on

Written by Oluwatosin Fatade

There are majorly 4 types of blood groups commonly known to us, and they have been ascribed their appellations following the ABO blood group typing. They are so named based on the type of blood cells found on the particular sample being tested, such that a person with blood group A has the A-antigen on the red blood cell, B blood group has B-antigen, AB has both A and B while O blood group has none (neither A nor B). There are many other types of blood groups but the above are the prevalent.
You must have also observed that a sign usually accompanies the above appellations, either a positive or negative. Thus, we have A +ve or –ve, B +ve or –ve, AB +ve or –ve, O +ve or –ve. The positive and negative signs are not arbitrary nor do they have anything to do with arithmetic. The ABO blood grouping system is one of many, the positive and negative belong to yet another grouping system of medical importance hence its prominence; this grouping system is the Rhesus grouping. There are two possibilities in the Rhesus grouping; it is either a Rhesus D factor is present on the red blood cell (in which case it is positive) or it is absent (negative).
The proper appellation of the mix of the ABO and Rhesus grouping will therefore appear as {A ‘Rh D’ positive} for a person with the A-antigen and Rhesus factor present on the red blood cell.

Of the 4 possibilities in the ABO and Rhesus mix, several distribution have been reported among Nigerians based on research work in different parts. The common indices to all however and what is most observed in clinical practice is that the Rhesus negative is not as common as the positive.

The importance of the Rhesus system as hinted earlier is brought to the fore in pregnancy. Let’s consider the scenario below for the purpose of explanation:

You’re O negative and your husband is O positive, your child can be either positive or negative. If negative, no problem but there’s no way to know the baby’s blood group until you’ve delivered. The way to know before delivery is cumbersome and unnecessary.
If the baby is positive, that’s where the concern comes. A concern that is well taken care of by the Rhogam injection.
Usually, for mothers who are O negative, it is just safe to assume the baby is positive since we don’t know for sure.

Rhogam injection is given to prevent Rhesus isoimmunisation which can occur whenever there is a risk or actual mixing of baby’s blood and mother’s blood. e.g any case of trauma, accident, physical assault or violence, abortion or miscarriage, delivery. It is to be administered when such mixing is suspected, a woman who has duly registered her pregnancy in a proper health facility will be put through this. The injection is to be administered within 72 hours of delivery.

O negative just means O Rhesus D negative, meaning you do not have the rhesus factor at all. Same way you are O because you don’t have either of A or B. So O positive which is the assumed blood group of the baby means the baby has rhesus factor, rhesus D positive.
So if there’s mixing, the baby doesn’t get affected. It’s the mother, the mothers body recognises the positive rhesus factors as foreigners and forms soldiers against them (antibodies). These soldiers don’t do anything in or to that particular pregnancy. But in any other pregnancy after that, remember soldiers against rhesus positive have been formed already, if they see any positive, they’ll fight it. Because they already know it as a foreigner unlike first time when they were “caught unawares”.
What Rhogam does is to clear these soldiers if they are formed so as to protect the subsequent pregnancies.

Once a woman has the Rhesus factor, meaning ‘positive’ follows the appellation of the corresponding ABO system she has, there will be no need for Rhogam since she cannot be sensitised to what she already has. Her body cannot form soldiers against positive rhesus factors which she already has in her own body!

If a woman has an abortion either spontaneously (what is commonly called miscarriage) or induced (meaning she sought it herself), it will be necessary to also put into consideration the blood group of both parties that formed the pregnancy to determine whether Rhogam will be needed or not.

Note that the different blood grouping systems are not a basis for discouraging intending couples from getting married as is being advocated in the case of Genotype to curb the prevalence of sickle cell anaemia.

Finally, know your blood group today (or tomorrow). Register your pregnancy in a hospital, ensure it’s not a quack you’re seeing. When you get pregnant, don’t miss your scheduled clinic visits and don’t hesitate to get more clarifications from your health care provider.

Got any questions or clarifications? Comment them below or send a mail to

Try out these questions; first 5 correct answers get rewarded (all answers must be correct).
Send your answers, Name, Email address and Phone Number to with the subject “QUIZ”. Entries close by midday tomorrow, Friday 26th May.

1. A man is AB +ve and his wife is B negative, will there be a possible need for Rhogam injection when she becomes pregnant?
2. Mention 4 other blood grouping systems asides ABO and Rhesus systems.
3. Is it advisable for a man with A positive blood group to father a child with a woman with O negative blood group?
4. What is the purpose of Rhogam Injection?

Terms & Conditions
– Medical doctors, nurses and health professionals are not permitted to send in entries
– All answers must be correct.
– No late entries
– No double submissions, no anonymous submissions
– All answers must be accompanied by your full name, email address and phone number.

Written by: Admin

A firm believer in the grace-full finished works of Christ, a grateful beneficiary of God's never-ending grace, sights the good in all, gives the benefit of doubt always, hates Religion, loves the Lord. Medical doctor



Thanks so much for this piece.. Its educative. God bless you


are you really going to leave without saying anything?

%d bloggers like this:
Skip to toolbar