What is the Rh Factor?

The Rh factor, or rhesus factor, is a protein on the surface of your red blood cells making people either Rh positive or Rh negative. It is important to know when you are pregnant, if you are Rh negative because you can develop antibodies against your Rh positive baby. If a small amount of your blood mixes with the baby’s, your body will react as if you are allergic to the baby and attack leading to anemia, brain damage or death for the baby.