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Group B Streptococcus (Group B Strep) and Pregnancy

Pregnant woman holding her stomachGroup B strep (GBS) is a type of bacteria that is often found in the vagina and rectum of healthy women. In the United States, about 1 in 4 women carry this type of bacteria. Women of any race or ethnicity can carry these bacteria. Being a carrier for these bacteria does not mean you have an infection. It only means that you have group B strep bacteria in your body.

However, group B strep bacteria, passed from a mother to her baby during childbirth, can cause serious illness in newborns. GBS is a leading cause of life-threatening infections in newborns, including pneumonia (lung infection), sepsis (blood infection), meningitis (infection of the lining of the brain and spinal cord), and other problems.

Group B strep infections in newborns can be prevented.

Action Steps

Each time you are pregnant, you need to be tested for GBS. It doesn't matter if you did or did not have this type of bacteria before; each pregnancy is different.

  • When 35 to 37 weeks pregnant (9th month), ask your health care provider for a GBS test.
  • If the test is positive for group B strep, talk with your doctor about a plan for labor.
  • Continue regular check-ups, and always call the doctor or nurse if there are any problems.
  • Make sure to tell the doctor or nurse about any allergies to penicillin or other antibiotics.
  • If you have not had a GBS test when labor starts, remind the staff that you do not know your GBS status


Learn more about preventing group B strep infections in newborns.

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