Many things can take you by surprise during pregnancy… those weird early signs of pregnancy, bizarre dreams, and “pregnancy brain,” to name a few. But one big surprise that is no fun is a positive Group B Strep (GBS) result during pregnancy.

In this post we’ll discuss:

  • What is Group B Strep?
  • How do doctors test for GBS?
  • Plus, what a positive GBS diagnosis means for your pregnancy and your baby

What is GBS During Pregnancy?

GBS is NOT the same bacterium that causes strep throat, which is from group A.

Our bodies have all kinds of bacteria in them, particularly in the bladder, vagina, intestines, and rectum. GBS is a type of bacteria found in 25 percent of all healthy adult women. 

Women who test positive for GBS during pregnancy are considered to be colonized (aka carriers), meaning the bacteria lives in their body without causing illness. The bacteria can come and go, without causing health issues or symptoms for most people. However, it is a bacterium, so there can be serious risks for those who are vulnerable, such as babies, elderly people, and those with chronic medical issues.

Note: There are many references for GBS during pregnancy—Group B Streptococcus Infection, Group B Strep, Baby Strep—that all mean the same thing. For consistency, we’ll use the two most common terms—Group B Strep and GBS.

What Causes Group B Strep?

An adult can get Group B Strep from food, water, or things you touch. Although it can be sexually transmitted, GBS is not a sexually transmitted disease. Like germs from a cold, GBS is simply passed from person to person through everyday contact. (Source)

A GBS diagnosis has nothing to do with a woman being clean or not! 

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How is GBS Diagnosed?


At every prenatal appointment, your healthcare provider will test your urine for protein, sugar, and bacteria. In heavy colonizers, GBS may show up during routine urine screenings. (The same is true for gestational diabetes and preeclampsia.) Approximately 2-7 percent of pregnant women test positive for GBS in their urine during these appointments.

Swab test

But most people won’t get diagnosed with GBS until their healthcare providers does a swab test between 35 and 37 weeks. In some cases, your provider may let you test early. This way, if you test positive, you can take action to try to rid your system of the bacteria.

During the swab test, your healthcare provider will:

  1. Use a sterile swab to swipe from your vagina to your rectum.
  2. Send the sample to the lab for analysis. This usually takes 24-48 hours.T

The test itself only takes a few seconds, but it checks to see if the bacteria has colonized the vaginal canal or rectum, both of which can affect baby. Once the result of your Group B Strep test are in, your doctor will generally provide the results over the phone, though they’ll want to schedule a follow-up appointment if you test positive.

GBS Treatment

If you test positive for GBS, your healthcare provider will offer one of two methods of treatment: preventive (most common in the U.S.) or risk-based.

Check out this post for more information about your treatment options, plus home remedies to promote healthy vaginal flora before birth. 

GBS During Pregnancy: Risks and Complications

It’s important to know that even if you have GBS during pregnancy, your baby will probably be healthy.

Even if mama has Group B Strep and is NOT treated, there is only a 1-2 percent chance that baby will get an infection. Antibiotics during labor further decrease the risk to about 0.2 percent.(source)

That said, GBS should be taken seriously, because infections can be life-threatening for baby. If baby contracts an infection from GBS, it is usually treatable, but it can be serious and very scary. Complications range from fever to more critical issues, such as pneumonia, sepsis, and meningitis (an infection of the fluid and lining of the brain). In 2-3 percent of full-term babies, a GBS infection is fatal. (source)

How Does Baby Get GBS?

Baby can contract GBS if he/she comes in contact with fluid that contains Group B Strep bacteria.

  • Baby will come into contact with bacteria during the time between the water breaking and delivery, since a woman’s rectum and vagina are where colonized GBS is most often found.
  • In rare cases, the bacteria can cross through the amniotic sac before it’s ruptured. (source)

The good news? The vast majority of babies will not develop an infection. Though approximately half of babies may be colonized, only 1 in every 200 babies born to a GBS-colonized mother will actually develop an infection. (source)

Can Baby Get GBS During a C-Section?

If you are GBS positive and your water breaks, baby can be colonized with Group B Strep—regardless of whether you end up having a vaginal birth or a C-section. This is because the physical barrier protecting baby, aka the bag of waters, has been compromised. The longer baby remains inside the mother after her water breaks, the higher the risk of infection (for both mom and baby).

How to Prevent Baby From Getting Group B Strep After Delivery

There’s no 100 percent effective way to prevent Group B Strep from passing to baby if mama has it (hey, even antibiotics aren’t foolproof!). Still, there are a few things to help give baby the best chance at fighting the bacteria.

  • Delay baby’s first bath: The waxy, cheese-like coating baby is born with, called the vernix, has natural antibacterial properties. This research found the vernix contained substances that target a large variety of pathogens, including Group B Strep. So, don’t wash it off, rub it in!
  • Practice skin-to-skinAsk your healthcare provider to place baby on your bare chest immediately following delivery. Research suggests skin-to-skin, or kangaroo care, may reduce the risk of baby being colonized by bacteria. It also reduces stress levels and stabilizes blood sugar, breathing, and blood pressure.
  • Breastfeed: Immediate breastfeeding can help protect baby, because colostrum—early milk—is loaded with immunological components. In fact, research suggests its primary function is to be immune-boosting rather than nutritional.

Be Aware of Late Onset GBS Positive in Baby

If your birth went fast or you weren’t able to get onto antibiotics, it’s possible for baby to come into contact with GBS bacteria. In some cases, baby may not present symptoms of infection until 7 days or up to 12 weeks after birth. This is called Late Onset GBS. (source

Warning signs include:

  • Excessive irritability
  • Blank or trance-like expression
  • Bulging fontanelle (soft spot)
  • Sensitivity to bright light
  • Stiff body or involuntary jerking movements
  • Pale or blotchy skin

Contact your child’s pediatrician immediately if you notice any of these symptoms.

How About You?

Did you test positive for GBS during pregnancy? How did GBS during pregnancy affect your childbirth? Share with us in the comments below.