Rh factor, also known as Rhesus factor, is a protein found on the surface of red blood cells. The Rh factor is inherited. If a person has Rh factor, they’re Rh positive. If they do not, they’re Rh negative. More people have Rh-positive blood than Rh-negative blood by a wide margin.
Rh incompatibility is a condition that occurs during pregnancy if a mother is Rh negative and a foetus is Rh positive. It can be identified and treated. The Rh factor determines the positive or negative factor of blood type. The blood types are O positive, O negative, AB positive, AB negative, B positive, B negative, A positive, and A negative.
Rh factor usually does not have implications for overall health. The only exceptions are pregnancy, when a mother may be incompatible with the foetus’s blood type, and if a person needs a transfusion.
If untreated during pregnancy, symptoms of Rh incompatibility can manifest. They do not affect the mother, but they will affect the baby.
Symptoms during pregnancy include:
Symptoms after birth include:
Testing for Rh incompatibility in early pregnancy is a crucial step to prevent the development of further sickness.
The cause of Rh incompatibility is a pregnancy in which the mother has Rh-negative blood, and the foetus has Rh-positive blood. If a mother has Rh-positive blood, there is no chance of Rh incompatibility.
A Rh-negative mother’s immune system will react to the Rh proteins on the surface of the baby’s red blood cells, causing an attack on the foetus’s red blood cells.
Rh incompatibility is not likely to happen during a first-time pregnancy unless complications arise. However, it will happen during any further pregnancies in which the mother is Rh negative and the foetus is Rh positive.
While specific molecules like immune system proteins and oxygen can pass between the mother’s and foetus’s blood, the mother and foetus do not share blood. During a first pregnancy, it is not likely the mother’s blood will mix with the foetus’s blood until after birth.
However, during a second pregnancy with a Rh-negative child, the body immediately recognizes Rh proteins as foreign, causing the immune system to attack the foetus’s red blood cells (Rh disease).
There are no known risk factors for Rh incompatibility.
Rh incompatibility is tested in the first trimester. A doctor will take a blood sample to determine if you’re Rh-negative or Rh-positive.
The most significant complication of Rh incompatibility is Rh disease, which will occur if treatment is not provided quickly enough.
If you’re Rh-positive, there’s no risk of Rh incompatibility. If you’re Rh negative, your doctor will give you Rh immunoglobulin at around 28 weeks and again 3 days before delivery to stop the formation of immune system proteins that would attack the baby’s red blood cells.
Rh incompatibility is not preventable because it relies on blood type. The best preventative measure is to find out your Rh factor as soon as you know you’re pregnant. Receiving Rh immunoglobulin injections after any potential contact with the foetus’s blood is the best way to ensure your baby is born healthy.