Prevention in Newborns
The two most important ways to prevent early-onset (occurs in babies younger than 1 week old) group B strep disease include:
- Testing all pregnant women for group B strep bacteria late in pregnancy (ideally between 35 and 37 weeks pregnant)
- Giving antibiotics during labor to women who test positive for group B strep bacteria
Testing Pregnant Women
Pregnant women should be tested, or screened, for group B strep bacteria in her vagina and rectum when she is 35 to 37 weeks pregnant. The test is simple and does not hurt. A sterile swab (“Q-tip”) is used to collect a sample from the vagina and the rectum and is then sent to a laboratory for testing.
About 1 out of every 4 (about 25%) pregnant women carry group B strep bacteria in their rectum or vagina. Those women are considered group B strep positive. A woman may test positive for the bacteria at some times and not others. That’s why it’s important for all pregnant women to be tested for group B strep bacteria between 35 to 37 weeks of every pregnancy.
Did You Know?
A pregnant woman who tests positive for group B strep bacteria and gets antibiotics during labor can feel confident knowing that she has only a 1 in 4,000 chance of delivering a baby with group B strep disease. If a pregnant woman who tests positive for group B strep bacteria does not get antibiotics at the time of labor, her baby has a 1 in 200 chance of developing group B strep disease. This means that those infants whose mothers are group B strep positive and do not get antibiotics have over 20 times the risk of developing disease than those who do receive preventive antibiotics.
A woman who has group B strep bacteria in her body usually does not feel sick or have any symptoms (asymptomatic). However, she is at an increased risk for passing the bacteria to her baby during birth.
Women should talk to their doctor about their group B strep status.
Antibiotics During Labor
To help protect their babies from infection, pregnant women who test positive for group B strep bacteria in the current pregnancy should receive antibiotics (medicine that kills bacteria in the body) through the vein (IV) during labor. Also, pregnant women who have group B strep bacteria in their urine during the current pregnancy or who had a previous baby develop group B strep disease should get antibiotics during labor. These women do not need to be screened at 35 to 37 weeks because they should receive antibiotics no matter the results. Pregnant women who do not know if they are positive for group B strep bacteria when labor starts should be given antibiotics if they have:
- Labor starting at less than 37 weeks (preterm labor)
- Prolonged membrane rupture (water breaking 18 or more hours before delivery)
- Fever during labor
Antibiotics help to kill some of the group B strep bacteria that are dangerous to the baby during birth. The antibiotics help during labor only — they cannot be taken before labor, because the bacteria can grow back quickly. Penicillin is the most common antibiotic that is given, but women who are severely allergic to penicillin can be given other antibiotics. Women should tell their doctor or nurse about any allergies during a checkup and try to make a plan for delivery. When women get to the hospital, they should remind their doctor and any staff if they have any allergies to medicines.
Penicillin is very safe and effective at preventing the spread of group B strep bacteria to newborns during birth. There can be side effects from penicillin for the mother, including a mild reaction to penicillin (in about 1 out of every 10 women). There is a rare chance (about 1 out of every 10,000 women) of the mother having a severe allergic reaction that requires emergency treatment.
Unfortunately, the method recommended to prevent early-onset disease (giving women who are group B strep positive antibiotics through the vein (IV) during labor) does not prevent late-onset disease (occurs in babies 1 week through 3 months old). Although rates of early-onset disease have declined, rates of late-onset disease have remained about the same since 1990. A strategy has not yet been identified for preventing late-onset group B strep disease.
Currently, there is no vaccine to help mothers protect their newborns from group B strep bacteria and disease. Researchers are working on developing a vaccine, which may become available one day in the future.
Antibiotics taken by mouth instead of through the vein and antibiotics taken before labor and delivery are not effective at preventing group B strep disease in babies. Birth canal washes with the disinfectant chlorhexidine also do not reduce the risk of a mother spreading group B strep bacteria to her baby or her baby developing early-onset disease. To date, receiving antibiotics through the vein during labor is the only proven strategy to protect a baby from early-onset group B strep disease.
- Page last reviewed: May 23, 2016
- Page last updated: May 23, 2016
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