Preventing Group B Strep Disease
There are currently no vaccines to prevent group B strep (GBS) disease but they are under development. There are things doctors and midwives can do to prevent GBS disease during the first week of a newborn’s life. Unfortunately, experts have not yet identified effective ways to prevent GBS disease in people older than one week old.
Preventing illness in newborns
The two best ways to prevent GBS disease during the first week of a newborn’s life are
- Testing pregnant women for GBS bacteria
- Giving antibiotics, during labor, to women at increased risk
Testing pregnant women
The American College of Obstetricians and Gynecologists (ACOG) and American College of Nurse-Midwives (ACNM) recommend women get tested for GBS bacteria when they are 36 through 37 weeks pregnant.
The test is simple and does not hurt. Doctors and midwives use a sterile swab (“Q-tip”) to collect a sample from the vagina and the rectum. They send the sample to a laboratory for testing.
Women who test positive for GBS bacteria are not sick. However, they are at increased risk for passing the bacteria to their babies during birth.
GBS bacteria come and go naturally in people’s bodies. A woman may test positive for the bacteria at some times and not others. That is why women get tested late in their pregnancy, close to the time of delivery.
Antibiotics during labor
Doctors and midwives give antibiotics to women who are at increased risk of having a baby who will develop GBS disease. The antibiotics help protect babies from infection, but only if given during labor. Antibiotics cannot be given before labor begins because the bacteria can grow back quickly.
Doctors and midwives give the antibiotic by IV (through the vein). They most commonly prescribe a type of antibiotic called beta-lactams, which includes penicillin and ampicillin. However, they can also give other antibiotics to women who are severely allergic to these antibiotics. Antibiotics are very safe. For example, about 1 in 10 women have mild side effects from receiving penicillin. There is a rare chance (about 1 in 10,000 women) of having a severe allergic reaction that requires emergency treatment.
Antibiotics are very effective at preventing GBS disease in newborns. Consider the following examples:
Tanya
Her baby has a 1 in 4,000 chance of developing GBS disease.
Emma
Her baby has a 1 in 200 chance of developing GBS disease.
Because Emma did not get antibiotics during labor, her baby is 20 times more likely to get GBS disease compared to Tanya’s baby.
Most babies born to women who tested positive for GBS bacteria do not need treatment if their mother received antibiotics during labor.
Strategies proven not to work
The following strategies are not effective at preventing GBS disease in babies:
- Taking antibiotics by mouth
- Taking antibiotics before labor begins
- Using birth canal washes with the disinfectant chlorhexidine