Pregnancy Information Center
Information, Symptoms, Treatments and Resources
Your Guide to Prenatal Tests
Group B Strep Test (GBS)
Group B Strep Test (GBS)
When it’s done: Around 36 or 37 weeks
You’ll have a vaginal and rectal swab to check for group B streptococcus bacteria (GBS). This bacteria isn’t usually harmful to the mother, but it can cause pneumonia and other serious infections in the newborn.
If you test positive for GBS, it means you’re a carrier — but it doesn’t mean your child will have a GBS infection at birth. If you’re GBS positive, you’ll be offered antibiotics in labor.
By Jenilee Matz, MPH. Published on May 6, 2013. Jenilee is a medical writer, health educator and triathlete based in Charlotte, NC. Updated on December 30, 2015.
Reviewed by Elisabeth Aron, MD, MPH, FACOG on September 27, 2015.
