See Also: Rh Factor Incompatibility
Rh factor blood test
Overview Rhesus (Rh) factor is an inherited protein found on the surface of red blood cells. If your blood has the protein, you're Rh positive. If your blood lacks the protein, you're Rh negative.
Rh positive is the most common blood type. Having an Rh negative blood type is not an illness and usually does not affect your health. However, it can affect your pregnancy. Your pregnancy needs special care if you're Rh negative and your baby is Rh positive (Rh incompatibility). A baby can inherit the Rh factor from either parent. Your health care provider will recommend a blood type and Rh factor screening test during your first prenatal visit. This will identify whether your blood cells carry the Rh factor protein.
Why it's done During pregnancy, problems can occur if you're Rh negative and the baby you're carrying is Rh positive. Usually, your blood doesn't…