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 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, ...