One important thing to be checked when finding out your genotype and blood group is your Rhesus factor. This is because it determines your blood compatibility and it’s particularly important in pregnancy.
Rh factor was first named after being identified in the blood of Rhesus Monkeys that were used to do tests. It’s an antigen present on our red blood cells. A person can either have a Rh factor or not on their red blood cells.
The person with Rh factor on his or red blood cells is said to be Rhesus positive (Rh+). This means that such person will not make anti-Rhesus antibodies. The person without the Rh factor on their red blood cells is said to be Rhesus negative (Rh-). This means that, such person will produce anti-Rh antibodies. In other words, a Rh+ person can receive both a Rh+ and a Rh- blood while a Rh- person can only receive a Rh- blood.
Antibodies are proteins made by our immune system which fights foreign substances – anything recognised by the body to cause harm, and this might mean blood cells from a person to another that they are not compatible with. This incompatibility leads to haemolysis (breakdown of red blood cells), – Rhesus disease. This happens when a pregnant woman has Rhesus negative blood and the baby in-utero has Rhesus positive blood.
However, before an attack is launched by the antibodies, the woman must have been sensitised to produce those antibodies that would be ready to fight any secondary exposure. This means that, the first pregnancy of a Rhesus negative woman with a Rhesus positive baby would be just fine. Simply because, the antibodies develop after her first exposure, even if she miscarries or aborts.
Hence, she is sensitised and therefore, subsequent exposure would trigger immediate immune response that fights the blood cells of her baby. This is made possible because, the antibodies are able to cross the placenta to the baby. These antibodies still attack the baby few months after being born.
One of the products of haemolysis is bilirubin and because of the baby’s immature organs, the liver cannot effectively excrete bilirubin leading to hyperbilirubinemia (too much bilirubin in the blood). This reflects on the baby as jaundice.
Good thing is, Rhesus Disease can be prevented –
- If the woman ensures that she is screened antenatally to determine whether she is Rhesus positive or negative.
- An injection known as anti-D immunoglobulin would be given to her at some points in her pregnancy which will help to remove the Rhesus positive blood cells of the fetus to prevent her from being sensitised.
Sadly, once there is sensitisation, these injections are not very useful.
A baby born with Rhesus disease also known as haemolytic disease of the newborn would require treatment otherwise, it can cause the baby to be blind, deaf, or experience difficulties in learning. Treatment is dependent on the severity. Most often, the baby would need to be admitted in a neonatal unit and phototherapy, blood transfusion or antibodies injections are given. Prognosis is usually good if treated.
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