The Rh factor is a type of protein that's usually found on red blood cells. When you have this protein, you’re considered Rh positive. About 85% of people are Rh-positive. The rest are Rh-negative.

When a woman and her unborn baby carry different Rhesus (Rh) protein factors, their condition is called Rh incompatibility. It occurs when a woman is Rh-negative and her baby is Rh-positive. The Rh ...

When you’re pregnant, you may learn that your baby isn’t your type — blood type, that is. Every person is born with a blood type — O, A, B, or AB. And they’re also born with a Rhesus (Rh) factor, ...

The rhesus factor, or Rh factor, is a protein that may be present on the surface of red blood cells (RBCs). If RBCs contain the Rh antigen, they are Rh-positive, and if not, they are Rh-negative. It ...