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.

The Rh factor test is routine for nearly all pregnant women. It’s usually conducted when your blood sample is taken during your first prenatal care visit. The results will determine if your blood has ...

The new noninvasive test, using a blood sample of the pregnant woman, is as reliable as the conventional test using a blood sample of the newborn. Studies on benefit and harm are still lacking. If the ...

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 ...

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 ...