- In the United States, group B strep bacteria is a leading cause of meningitis and bacteremia in a newborn’s first week of life (early-onset disease). Meningitis is an infection of the tissue covering the brain and bacteremia is a bloodstream infection.
- About 1 in every 4 pregnant women carry group B strep bacteria in the rectum or vagina.
- Newborns are at increased risk for group B strep disease if their mother tests positive for group B strep bacteria during pregnancy.
- Doctors should test pregnant woman for group B strep bacteria when they are 35 to 37 weeks pregnant.
- Doctors can prevent most early-onset group B strep disease in newborns by giving pregnant women antibiotics through the vein (IV) during labor.
- Pregnant women should get antibiotics during labor if
- They test positive for group B strep bacteria during their current pregnancy
- They have group B strep bacteria in their urine anytime during their current pregnancy
- They had a previous baby that developed group B strep disease
- A pregnant woman who tests positive for group B strep bacteria and gets antibiotics during labor has only a 1 in 4,000 chance of delivering a baby who will develop group B strep disease. If she does not receive antibiotics during labor, her chance of delivering a baby who will develop group B strep disease is 1 in 200.
- The antibiotics used to prevent early-onset group B strep disease in newborns only help during labor. Pregnant women cannot take them before labor, because the bacteria can grow back quickly.
- Group B strep bacteria may come and go in people’s bodies without symptoms.
- The rate of serious group B strep disease increases with age. The average age of cases in non-pregnant adults is about 60 years old.
Page last reviewed: May 29, 2018