Group B Strep: FAQs

If you had a previous baby who got sick with group B strep disease, or if you had a urinary tract infection (bladder infection) during this pregnancy caused by group B strep, you also need to get antibiotics through the vein (IV) when your labor starts.

Question: How do you find out if you carry group B strep during pregnancy?

Answer: CDC’s revised guidelines recommend that a pregnant woman be tested for group B strep 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. This is sent to a laboratory for testing.

Question: What happens if my pregnancy screening test is positive for group B strep?

Answer: To prevent group B strep bacteria from being passed to the newborn, pregnant women who carry group B strep should be given antibiotics through the vein (IV) at the time of labor or when their water breaks.

Question: Are there any symptoms if you are a group B strep carrier?

Answer: Most pregnant women have no symptoms when they are carriers for group B strep bacteria. Sometimes, group B strep can cause bladder infections during pregnancy, or infections in the womb during labor or after delivery.

Being a carrier (testing positive for group B strep, but having no symptoms) is quite common. Around 25% of women may carry the bacteria at any time. This doesn’t mean that they have group B strep disease, but it does mean that they are at higher risk for giving their baby a group B strep infection during birth.

Question: What if I don’t know whether or not I am group B strep positive when my labor starts?

Answer: Talk to your doctor about your group B strep status. Pregnant women who do not know whether or not they are group B strep positive when labor starts should be given antibiotics if they have:

  • labor starting at less than 37 weeks (preterm labor);
  • prolonged membrane rupture (water breaking more than 18 hours before labor starts);
  • fever during labor.

Question: What are the risks of taking antibiotics to prevent group B strep disease in my newborn?

Answer: Penicillin is the most common antibiotic that is given. If you are allergic to penicillin, there are other antibiotics that can be given. Penicillin is very safe and effective at preventing group B strep disease in newborns. There can be side effects from penicillin for the woman, including a mild reaction to penicillin (about a 10% chance). There is a rare chance (about 1 in 10,000) of the mother having a severe allergic reaction that requires emergency treatment.

However, a pregnant woman who is a group B strep carrier (tested positive) at full-term delivery who gets antibiotics can feel confident knowing that she has only a 1 in 4000 chance of delivering a baby with group B strep disease. If a pregnant woman who is a group B strep carrier does not get antibiotics at the time of delivery, 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 carriers and do not get antibiotics have over 20 times the risk of developing disease than those who do receive treatment.

Question: Can group B strep cause stillbirth, pre-term delivery, or miscarriage?

Answer: There are many different factors that lead to stillbirth, pre-term delivery, or miscarriage. Most of the time, the cause is not known. Group B strep can cause some stillbirths, and pre-term babies are at greater risk of group B strep infections. However, the relationship between group B strep and premature babies is not always clear.

Question: Will a C-section prevent group B strep in a newborn?

Answer: A C-section should not be used to prevent early-onset group B strep infection in infants. To learn more about C-sections and group B strep prevention, please review this section of the revised group B strep guidelines. If you need to have a C-section for other reasons, and you are group B strep positive, you will not need antibiotics for group B strep only, unless you begin labor or your water breaks before the surgery begins.

Question: What should I do if my water breaks early?