The Rh factor, or Rhesus factor, is a protein found on the surface of red blood cells. If your blood cells have this protein, you are Rh-positive (Rh+). If not, you are Rh-negative (Rh−).

The Rh factor is particularly significant during pregnancy. If an Rh-negative mother is carrying an Rh-positive baby, there is a risk of Rh incompatibility. This occurs when the mother’s blood and the baby’s blood mix, potentially leading the mother to produce antibodies against the Rh-positive blood cells.

Rh sensitization happens when an Rh-negative mother develops antibodies after exposure to Rh-positive blood. It usually does not affect the first pregnancy. However, these antibodies can cross the placenta in future pregnancies and attack the baby’s red blood cells.

If Rh sensitization is not prevented, antibodies from the mother can destroy the baby’s red blood cells. This condition is known as Hemolytic Disease of the Fetus and Newborn (HDFN). HDFN can lead to severe anemia, jaundice, heart failure, brain damage, stillbirth, or newborn death.

Early blood group and Rh testing during pregnancy helps identify mothers who may need special care. Knowing your Rh status allows healthcare providers to plan timely prevention and protect both current and future pregnancies.

Rh incompatibility can be prevented with Rh immune globulin (RhIg). This injection stops the mother’s body from forming harmful antibodies. RhIg is usually given during pregnancy and after delivery if the baby is Rh-positive.

You should discuss your blood group and Rh status during your first antenatal visit. If you are Rh-negative, your provider will guide you on monitoring and preventive treatment to ensure a safe pregnancy.