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Rh Factor
What is Rh Factor?

You’d never think your blood could cause your baby harm, but it can, if you don’t have your blood tested. You probably know your blood has a type—A, B, O, or AB. You also may know your blood is negative or positive. The Rh, or Rhesus Factor, is positive when your red blood cells are coated with a certain antigen, or protein. Only about 15% of people are Rh-negative, and it’s that rarer lack of this antigen that can cause problems for you and your unborn child.

The Rh factor doesn’t come into play until a Rh-negative mother and a Rh-positive partner create a child that’s Rh-positive. Though your bloodstream is separate from your baby’s, and nutrients are filtered through the placenta, there are times when your baby’s blood can mingle with yours. Your body can make antibodies against the intruding Rh antigens in a process known as sensitization

These antigens can cross the placenta and will attack your baby, treating it as if it were an invader instead of a welcomed guest for nine months. This attack on your fetus can result in hemolytic anemia, brain damage and death.

This sounds scary, but as long as you get your blood tested and screened for Rh factor, you’re on your way to a healthy pregnancy. If there is an Rh factor problem, your doctor will monitor your health and your baby’s closely. There is an injection your can receive that gives your body immunity before sensitization takes place. Called Rho (D) immune globulin, these injections are given in two parts, the first around week 28 and the second at least 72 hours after delivery. You may also receive a dose if you have amniocentesis testing or experience bleeding during pregnancy.

If you do develop antibodies toward your baby’s blood, there are measures your doctor can take, such as blood transfusions while your baby is still in your uterus. If this is your first pregnancy, you have little to worry about. Rh factor becomes more of a problem during subsequent pregnancies. In any case, go get your blood tested promptly so your doctor can have the results. Knowing the results will prepare you or set your mind at ease so you can have a healthy baby in your arms soon.

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