Rh factor and pregnancy

Each person's blood is one of four main types: A, B, AB, or O. Blood types are determined by the types of antigens found on blood cells. Antigens are proteins on the surface of blood cells that can trigger an immune system response. The Rh factor is a type of protein on the surface of red blood cells. Most people who have the Rh factor are Rh positive, while those who don't are Rh negative.

How do I know if I am Rh negative or Rh positive?

As part of your antenatal care, you will have blood tests to determine your blood type. If your blood lacks the Rh antigen, it is said to be Rh negative. If he has the antigen, he is said to be Rh positive. If the mother is Rh negative and the father is Rh positive, the fetus can inherit the father's Rh factor. It also makes the fetus Rh-positive. Problems can arise when there is an Rh factor in the blood of the fetus, but not in the mother's blood.

What can happen if I am Rh negative and pregnant?

If you are Rh negative, you may develop antibodies against an Rh positive baby. If a small amount of the baby's blood mixes with yours, which happens often, your body may react as if it were allergic to the baby. Your body may make antibodies against the Rh antigens in your baby's blood. This means that you have become sensitized and your antibodies can cross the placenta and attack your baby's blood.

They destroy the fetal red blood cells and cause anemia (a condition that occurs when there are few red blood cells in the blood). This condition is called hemolytic disease or hemolytic anemia. It can become severe enough to cause serious illness, brain damage, or even death of the fetus or newborn. Sensitization can occur whenever fetal blood mixes with maternal blood.

This can happen if an Rh-negative woman has had:

A miscarriage
An induced abortion or menstrual extraction
An ectopic pregnancy
Chorionic villus sampling
A blood transfusion

How to prevent problems?

A blood test can give you your blood type and Rh factor.
Antibody screening is another blood test that can show if an Rh-negative woman has developed antibodies to Rh-positive blood.
An injection of Rh immunoglobulin (RhIg), a blood product that can prevent sensitization of an Rh-negative mother.

When are RhIgs used?

RhIg is used during pregnancy and after childbirth:

If a woman with Rh-negative blood has not been sensitized, her doctor may suggest she administer RhIg around the 28th week of pregnancy to prevent sensitization during the rest of the pregnancy.
If the baby was born with Rh-positive blood, the mother should receive another dose of RhIg to prevent the production of antibodies against Rh-positive cells that she may have received from the baby before and during birth.
RhIg treatment is only useful for the pregnancy in which it is given. Every pregnancy and every birth of an Rh-positive baby requires repeated doses of RhIg.
Rh negative women should also be treated after a miscarriage, ectopic pregnancy, or induced abortion to avoid the risk of the woman developing antibodies that could attack an Rh positive unborn child.

What other reasons can RhIg be given?

If and when an amniocentesis is performed, the fetal Rh-positive red blood cells may mix with the mother's Rh-negative blood. This will cause it to produce antibodies, which will require an injection of RhIg.

An Rh-negative mother can get RhIg after birth, even if she decides to tie and cut her fallopian tubes to prevent a future pregnancy, for the following reasons:

The woman may later decide to try to cancel the sterilization.
There is a small chance that sterilization will not prevent pregnancy.
If he needs a blood transfusion in the future, the treatment will prevent the production of antibodies.

What happens if antibodies develop?

If a woman develops antibodies, RhIg treatment no longer helps. A mother sensitized to Rh factor will be examined during pregnancy to see if the fetus develops the disease. The baby may be delivered on time, followed by a blood transfusion to the baby, which will replace the diseased blood cells with healthy blood. In more severe cases, the baby may be born early or receive a blood transfusion in the womb.

How common is Rh negative?

More than 85% of people are Rh-positive.
The Rh factor does not affect the overall health of a person.

Problems can occur during pregnancy when the baby's blood contains the Rh factor and the mother's does not, but in most cases this can be avoided with a medication called immunoglobulin (RhIg).