Group B Strep Screening

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If you are a new patient seeking prenatal care, please call 310-794-7274. If you are an established patient and need to reach labor and delivery, call 310-825-9111 for Westwood or 424-259-9250 for Santa Monica.

Frequently Asked Questions - Group B streptococcus

What is Group B streptococcus?

Group B streptococcus (also called group B strep) is a kind of bacteria that lives naturally in the digestive, urinary and reproductive tracts of men and women. In women, it often lives in the vagina and rectum. Group B strep is not sexually transmitted and usually does not cause serious illness. You can carry the bacteria without having any symptoms. This means you are “colonized” by the bacteria; however, it is not contagious. Also, how much bacteria you carry can change. Your number of bacteria may reach such a low level that it can’t even be detected.

Why do I need a Group B streptococcus screening test?

Most pregnant people colonized with group B strep have no symptoms or health effects. However, for some women, group B strep can cause infection during pregnancy. The most serious issue is that a woman carrying these bacteria can transmit it to her baby during delivery. This can be life-threatening for the newborn.

When should I get tested?

You will be tested for group B strep between 36 – 37 weeks of pregnancy. Your health care team member will use a swab to take a sample from your vagina and rectum. If group B strep is found in your urine during pregnancy, you are considered a carrier and no further testing is needed.

What if I test positive?

Your care team will give you IV antibiotics during labor to prevent you from passing group B strep to your baby during delivery. Antibiotics get rid of some of the bacteria that can harm your baby during birth. Antibiotics for group B strep only work if they are given while you are in labor. The most common antibiotic given for group B strep is penicillin. If you’re allergic to penicillin, please let your care team know. We may recommend allergy testing during pregnancy and may need to do special testing on the swab to see what other antibiotics are safe.

How can group B streptococcus affect a newborn?

Even though it’s rare for a baby to get group B strep, it can be serious when it happens. In rare cases, the bacteria can cause dangerous infections in the baby, such as pneumonia or meningitis.

What if I already had a baby with a group B streptococcus infection?

If group B strep was present in a previous delivery, you are considered high risk for passing this bacteria to your baby during labor and delivery. Your provider won’t screen you. Instead, you will automatically get antibiotics during labor.