Rh Factor in Pregnancy

During your first prenatal visit, your health care provider will take blood samples. Several things will be tested, including your blood type. The reason this is done is to check for the presence or lack of Rh factor in the blood. This is important because if your baby has Rh factor in his blood and you do not, this could cause problems in later pregnancies.

 

What is Rh factor and why does it matter? When you are told your blood type, the letter A, B, AB or O will be followed by a positive or negative. Rh is basically a protein that is present on the blood cells. Most people do have Rh factor, but about 15 percent of people do not. The positive, such as B+, means that Rh factor is present in the blood. If the blood type were O-, there would be no Rh factor in the blood. This is generally never a problem, unless you are an Rh negative mother with an Rh positive partner.