Please note: This information was current at the time of publication. But medical information is always changing, and some information given here may be out of date. For regularly updated information on a variety of health topics, please visit, the AAFP patient education website.

Information from Your Family Doctor

GBS Testing During Pregnancy


Am Fam Physician. 2012 Jul 1;86(1):115.

  See related article on perinatal group B streptococcal disease.

What is GBS?

GBS stands for group B streptococcus, or group B strep for short. It is a kind of germ that can live in a woman’s vagina, rectum, or urine. It is not the same germ that causes strep throat.

Why is it important?

If a pregnant women has GBS, the baby can catch it and get very sick. If you are pregnant, you need to be tested for GBS in your last month of pregnancy. There are no symptoms. Testing is the only way to tell if you have it.

How is the test done?

Your doctor will swab your vagina and rectum, and check your urine.

What happens if I have GBS?

If the test shows that you have GBS, you will get antibiotics through an IV while you are in labor. Make sure to tell your doctor if you are allergic to penicillin, because you will need to have a different medicine.

Where can I get more information?

Your doctor

AAFP’s Patient Education Resource

Web site:

Centers for Disease Control and Prevention

Web site:

This handout is provided to you by your family doctor and the American Academy of Family Physicians. Other health-related information is available from the AAFP online at

This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.


Copyright © 2012 by the American Academy of Family Physicians.
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