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If You Are Rh Negative

If you’re Rh negative, ask your healthcare provider about getting treated with Rho(D) immune globulin. Even if you miscarry or don’t deliver the baby, you will still need treatment. The health of any baby you have in the future depends on it.

When are you treated?

If your blood has not formed Rh antibodies, you’ll be treated during week 28 of your pregnancy. You also may be treated any time there’s a chance that fetal blood has mixed with yours. For example, this might be after an amniocentesis, a prenatal test. Or it might be if you have vaginal bleeding earlier than 28 weeks. Treatment is an injection of a medicine called Rho(D) immune globulin. Rho(D) immune globulin stops Rh antibodies from forming. It won’t harm you or the fetus. After you give birth, your baby’s blood will be tested. If it’s Rh positive, you’ll be given Rho(D) immune globulin again within 3 days. If it’s Rh negative, you won’t need Rho(D) immune globulin until your next pregnancy.

Preventing future problems

Your chance of forming Rh antibodies increases with each pregnancy. This is true even for an ectopic pregnancy (the fertilized egg is outside the uterus). It is also true for pregnancies that end in miscarriage or abortion. In these cases, you will most likely get a Rho(D) immune globulin injection. This is because your body can make Rh antibodies even if you don’t deliver a baby. Rh antibodies can cause problems in future pregnancies.


If antibodies have already formed (sensitization), Rho(D) immune globulin can’t protect the fetus. You and the fetus will need special care during pregnancy. Your healthcare provider will explain the details to you.

Online Medical Reviewer: Donna Freeborn PhD CNM FNP
Online Medical Reviewer: Irina Burd MD PhD
Date Last Reviewed: 6/1/2016
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