Group B Strep in Pregnancy: Testing, Treatment & What to Expect

What Is GBS?

Group B Streptococcus is a common bacterium that lives in the intestines, vagina, or rectum of about 1 in 4 women. It's not a sexually transmitted infection and doesn't mean you're unclean. Carrying GBS is usually harmless to adults but can cause life-threatening infection in newborns (pneumonia, sepsis, meningitis) if transmitted during vaginal delivery.

Testing (Weeks 36-37)

All pregnant women are screened for GBS between 36-37 weeks of pregnancy. Your provider swabs the vagina and rectum (quick, painless). Results take 1-3 days. GBS status can change between pregnancies and even within the same pregnancy, which is why testing is done late in pregnancy, close to the due date.

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Treatment During Labor

If you test positive, you'll receive IV antibiotics (usually penicillin or ampicillin) during labor, at least 4 hours before delivery for optimal protection. This reduces the risk of GBS transmission to baby from about 1 in 200 to less than 1 in 4,000. If you're penicillin-allergic, alternative antibiotics are available.

What If I'm GBS Positive?

Don't panic — GBS-positive status is common and manageable. Plan to arrive at the hospital early in labor to allow time for antibiotics. Inform your birth team of your GBS status. If your water breaks before labor starts, go to the hospital promptly for antibiotics. After delivery, your baby will be monitored for 24-48 hours for signs of infection.

Frequently Asked Questions

Is this information medically reviewed?

Yes. All Wermom medical content is reviewed by board-certified pediatricians and OB-GYNs. We follow guidelines from the AAP, ACOG, WHO, and CDC. However, this information is educational and doesn't replace personal medical advice from your healthcare provider.

When should I call my doctor?

Trust your instincts. If something feels wrong or you're concerned about your baby's health, call your pediatrician. They'd rather hear from you with a question that turns out to be nothing than miss something important. For emergencies (difficulty breathing, unresponsiveness, seizures), call 911 immediately.