Women's Health Texas – San Antonio

Rh Factor

The Rh factor is a protein on the surface of red blood cells

Most women have heard of Rh factor, but many women don’t understand what this important factor is. About 85% of mothers are positive for it. In those cases, this factor does not cause any problems with the pregnancy. However, women who are negative can have issues during pregnancy.

When a woman doesn’t have the factor, she is Rh negative

The factor can cause problems during pregnancy when a mother is negative and her baby is positive. If a mother is negative, she may produce antibodies that can cross the placenta and damage or destroy the baby’s red blood cells, leading to hemolytic anemia. This is a life-threatening condition for the baby. Mothers don’t experience problems during first pregnancies. However, problems can occur in later pregnancies if the woman doesn’t receive proper care during her first pregnancy.

What can an Rh negative mother expect?

During a woman’s first prenatal visit, our San Antonio OBGYNs order a variety of prenatal tests, including bloodwork that indicates whether she has the Rh factor. If she is negative, our doctors schedule a blood test called an antibody screen. It indicates whether a woman is Rh sensitized, meaning her body has begun to produce antibodies.

If a woman is not Rh sensitized yet, our physicians give her an injection of Rh immunoglobulin. This injection prevents her from producing antibodies that could harm the baby.

After the baby is born, we test his or her blood to determine whether the factor is present. If the baby is negative, there is no problem. However, if the baby is positive, the mother will need another injection.

Women who have the factor also need an Rh immunoglobulin injection in other situations where the mother and the baby’s blood may come into contact with each other.

  • Miscarriage or abortion
  • Ectopic or molar pregnancy
  • Amniocentesis or chorionic villus sampling
  • Our team takes a sample of fetal blood
  • The mother suffers any blunt trauma to the abdominal area
  • When a mother experiences bleeding during the pregnancy

What happens if the mother is Rh sensitized?

If a woman who does not possess the Rh factor becomes Rh sensitized and begins to produce antibodies that can harm her baby, an immunoglobulin injection will not help. Instead, our San Antonio OBGYNs, monitor the mother carefully. In rare cases, a baby with a sensitized mother may require a blood transfusion through the umbilical cord during pregnancy or after birth.

Our San Antonio OBGYNs treat high-risk pregnancies

Most women without the factor won’t experience complications, but if they do, we are here to handle the problems and any other high-risk pregnancy issues. Contact us to schedule an appointment. There are multiple ways to manage and treat an Rh sensitized pregnancy and we have years of experience to help you and your baby.