What could make a mother’s blood attack her unborn baby? What could make a woman in need of a blood transfusion panic because she can’t find a match? Why do some pregnant women have to take a special injection and others don’t? All these questions can be answered when the process of Rhesus Incompatibility in pregnancy is properly understood.
Rhesus Incompatibility in Pregnancy: Rhesus Factor
Apart from blood groups, which differentiate one type of blood from another, there is a protein located on the surface of red blood cells called the Rhesus factor. People who have this Rh factor are Rhesus positive, and those who don’t are Rhesus negative.
You may have heard statements like ‘I am O Positive,’ ‘I am B Negative.’ These positive and negative symbols are the Rhesus factor.
Rhesus Incompatibility in Pregnancy: Causes of Incompatibility
This happens when a woman who is Rhesus negative has her blood exposed to a Rhesus positive blood. This can be from her baby during a miscarriage or abortion or during a delivery; it can also occur when Rhesus positive blood is transfused into her, leading to the production of antibodies (bodyguards) against the foreign blood.
These antibodies do not go away but wait for another time when a Rhesus positive blood will be introduced and they attack it (this is the reason why most first babies are spared). If it is a subsequent Rhesus positive baby, it could lead to various risks.
Rhesus Incompatibility in Pregnancy: The Risks
- Varying degrees of anaemia and or Jaundice in newborn.
- Also, mismatched blood can lead to transfusion reactions.
Rhesus Incompatibility in pregnancy: The Prevention
The first thing is to know your blood group – the Rhesus factor is also done during this process. Pregnant women should have this done routinely as part of antenatal care.
Pregnant women that have not been previously sensitized will be given a special injection called Rhogam. This is given at 28-32 weeks of pregnancy and within 72 hours after putting to bed. However if the woman has been sensitized (this can be checked by checking her antibody levels), Rhogam cannot help and plays no role.
In such cases, ensure the baby is delivered in a centre that has good obstetric and neonatal care.
When getting married it is useful to know the Rhesus group of a partner; this does not disqualify you from getting married to that person — it only helps prepare well for your pregnancy.
NB: Not all Rh Negative women have Rh Incompatibility, and if both partners are Rh Negative, there is no risk for Rh Incompatibility and no need for Rhogam Injection during pregnancy.