What is the Role of RH Factor in Blood Types?


If you found that you are pregnant, one of the first and most important tests you should undergo is Rh factor in blood types. Rh factor plays a great role in your baby’s health, so it is essential to know this information as soon as you are pregnant.

RH Factor in Blood TypesBlood types, such as A, B, AB, and O are the descriptions of certain antigens found on red blood cells. A type of blood has A antigens on the red blood cells and B type has B antigens, AB type has A and B antigens and O type lacks A and B, but has others.

People who have Rh factor are called Rh positive and those who don’t have the Rh factor are Rh negative. So, during your prenatal checkup, you need to undergo the test to determine the Rh factor in blood types. For Rh-negative mother and Rh positive father, the baby can inherit Rh factor from father and make Rh-positive fetus. In case the fetus has the Rh factor and the mother doesn’t have Rh factor in blood types, then there is a chance of severe problems.

What happens if the mother is Rh positive and the fetus is Rh negative?

If an Rh-negative woman has Rh-positive fetus and the mother’s blood mixed with the fetus blood, then Rh antigens are produced in the fetus. These antigens can attack the baby’s blood and collapse the red blood cells and cause anemia. This situation is called as hemolytic anemia or hemolytic disease. This condition can become serious and cause brain damage or also the death of the fetus.

You may notice sensitization when the baby’s blood combines with mother’s blood. This condition occurs when the Rh negative mother has:

  • A previous miscarriage
  • Had induced abortion
  • Had ectopic pregnancy
  • A previous blood transfusion
  • Had chronic villus sampling

How to protect the fetus against the sensitization?

Initially, a pregnant woman should get tested for Rh factor in blood types as soon as her pregnancy is confirmed. Once it is confirmed, to prevent the sensitization, a blood product called as Rh immunoglobulin is injected into the mother for seven months. This product destroys the antigen produced by the fetus and exists in the mother’s blood prior she can produce antibodies. Nowadays, it is recommended that your newborn is also getting tested for Rh factor in blood types. This injection can prevent Rh disease in 99% of cases.


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