If you've tested positive for group B strep (GBS) during pregnancy, you may be wondering what it means and whether it could affect your baby.
Your prenatal care team is testing for group B Streptococcus, a type of bacteria that lives in your urinary tract, digestive system and reproductive tracts.
Usually, GBS doesn’t result in any health problems except when you’re pregnant. Testing positive for GBS can be scary. But don’t stress. The good news is that it is a very treatable condition.
Meghan MacCleary, DO, an OBGYN with Banner Health, helps answer questions about group B strep in pregnancy, how it’s tested for and ways you can protect your little one.
What happens if you test positive for group B strep?
Testing positive for GBS means you carry the bacteria, not that you are sick. Most people do not have symptoms, but your care team will take steps during labor to reduce the risk of passing it to your baby.
What is group B strep (GBS)?
“Approximately 1 in 4 pregnant people are colonizers or carriers of GBS, one of many bacteria that live in the body, but usually is found in the intestines, vagina and rectum,” Dr. MacCleary said.
Many people who test positive for GBS don’t have an active infection or symptoms. Pregnant women generally find out they are GBS positive when tested during their third trimester, between 36 and 37 weeks.
Most people who get sick from GBS infections are newborns exposed to the bacteria during birth. This is why getting tested for GBS and having the proper treatment plan in place before you deliver is important.
Is group B strep dangerous?
GBS is usually harmless in healthy adults, but it can cause serious infections in newborns if passed during delivery. That’s why testing and treatment during labor are important.
How do you get group B strep?
Being GBS-positive doesn’t mean you are unclean or have a sexually transmitted disease or infection (STD or STI). Anyone can carry this bacterium, even someone with no prior sexual experience.
“GBS isn’t something you can catch like the flu or a cold,” Dr. MacCleary said. “While it can be passed back and forth from skin-to-skin contact, it’s not considered a sexually transmitted disease.”
Who is at highest risk for complications from GBS?
Newborns, older adults or people with weakened or underdeveloped immune systems, such as diabetes or HIV (human immunodeficiency virus), are more likely to develop complications from GBS.
Some factors increase a pregnant person’s risk of having a baby who develops GBS. These include:
- Having a previous baby with GBS
- Developing a fever during labor
- Testing positive for GBS
- Going a long time between when your water breaks and when you deliver (18 hours or more)
- Having the bacteria found in your urine anytime during pregnancy
“In pregnant people, GBS can cause problems such as urinary tract infections (UTIs), pneumonia, bacteria in the blood, post-partum endometriosis and maternal sepsis,” Dr. MacCleary said. “However, the biggest risk could be for babies.”
While few babies who are exposed develop an infection, some babies who get GBS could develop life-threatening complications, including:
- Pneumonia, sepsis and meningitis
- Breathing problems
- Heart and blood pressure issues
- Hearing problems
- Gastrointestinal and kidney problems
What are the symptoms of GBS?
GBS doesn’t usually cause symptoms in healthy people. However, if you do have symptoms, these may include:
- Fever
- Nausea and vomiting
- Chest pain
- Difficulty breathing
Babies can develop the disease during childbirth or a week or more after birth (known as late-onset infection). The symptoms of infection in newborns may include:
- Fever
- Difficulty feeding
- Difficulty breathing
- Baby is tired or hard to wake up
How is group B strep treated during pregnancy?
Your health care provider will swab your vagina and rectum and will send the swab to a lab to see if the strep bacteria grow.
If you test positive for it, your labor and delivery team will give you an antibiotic through an IV during labor. The most common antibiotics to treat GBS are penicillin or ampicillin.
“This treatment works best if given at least four hours before childbirth,” Dr. MacCleary said. “This decreases the chances of your newborn getting the infection.”
According to the Centers for Disease Control and Prevention (CDC), your baby has a 1 in 200 chance of developing GBS if you don’t get antibiotics during labor, compared to 1 in 4,000 if you do
[Also read “Is It Safe to Take Antibiotics While I’m Pregnant.”]
Unfortunately, you can’t get treated for GBS before labor, as this bacterium can return after you stop taking the medicine.
Discuss with your health care provider how to include IV antibiotics in your birth plan, so your care team knows you’ll need them when you arrive. If you have a scheduled C-section, talk to your provider about the risks vs. benefits of starting IV antibiotics well before your surgery.
Can you get rid of group B strep?
GBS can come and go naturally in the body. Antibiotics given during labor help reduce the risk to your baby, but they do not permanently eliminate the bacteria.
What happens if you don’t get antibiotics in time?
Sometimes you can’t gauge how quickly your baby will come and may not make it to the hospital to receive your full dose of antibiotics.
If you don’t make it in time, your hospital or treating facility will watch your baby closely for signs of infection – usually 48 hours (about two days) after birth.
If your baby tests positive, they may need care in the NICU (neonatal intensive care unit) to receive IV antibiotics and be monitored for symptoms. Your baby may need other treatments if the infection is severe or if they have meningitis or pneumonia.
Frequently asked questions about group B strep
Is group B strep an STD?
No, it is not a sexually transmitted infection.
Can GBS harm my baby?
It can, but the risk is low, especially with proper treatment during labor.
Do all pregnant people get tested for GBS?
Yes, most are tested between 36 and 37 weeks.
Can GBS go away on its own?
Yes, it can come and go naturally in the body.
Takeaway
Testing positive for GBS during pregnancy is common and manageable. With proper care, the risk to your baby is low.
Talk to your provider about how being GBS-positive could affect your birth plan and any other concerns you may have. In most cases, testing positive won’t cause any problems, and your baby is healthy.
To find a Banner Health specialist near you, visit bannerhealth.com.
Related articles
- Rh Factor: How Does It Affect Your Pregnancy?
- When Should I Worry About Cramping During Pregnancy?
- Does My Baby Need a Vitamin K Shot? 5 Important Things to Know
Content in this article was updated on April 14, 2026.
