Group B Strep in Pregnancy: What You Need to Know

If you’re pregnant and you’ve heard about Group B Strep—or your provider mentioned you’ll be tested for it—you might be wondering what it is, why it matters, and what happens if you test positive.

Let’s talk about it. We’ll cover what Group B Strep is, when you’ll be tested, what a positive result means for you and your baby, and what your options are.

What Is Group B Strep?

Group B Streptococcus (GBS or Group B Strep) is a type of bacteria that naturally lives in many people’s bodies. It’s commonly found in the intestines, rectum, and vagina, and it’s usually harmless in healthy adults.

Here’s the important part: Group B Strep is not a sexually transmitted infection. It’s not something you “caught” or did anything to cause. About 1 in 4 pregnant people carry GBS, according to the Centers for Disease Control and Prevention (CDC). It comes and goes naturally—you might test positive in one pregnancy and negative in another.

For most people, having GBS doesn’t cause any symptoms or problems. But during pregnancy and birth, it’s something your healthcare team will want to know about because it can occasionally be passed to your baby during delivery.

Why Does Group B Strep Matter During Pregnancy?

Most babies born to people who carry GBS are perfectly healthy. However, in rare cases—without preventive treatment—GBS can be passed to the baby during labor and delivery and cause serious infections like sepsis, pneumonia, or meningitis.

The good news? According to the CDC, when pregnant people who test positive for GBS receive antibiotics during labor, the risk of their baby developing a GBS infection drops by about 80%.

When Will You Be Tested for Group B Strep?

The American College of Obstetricians and Gynecologists (ACOG) recommends that all pregnant people be tested for Group B Strep between 36 and 37 weeks of pregnancy.

This timing matters because GBS can come and go. Testing too early wouldn’t accurately predict whether you’re carrying it when you give birth.

What Does the GBS Test Involve?

The test is quick and simple. Your healthcare provider will use a swab to collect samples from your vagina and rectum. The whole process takes just a few seconds, and results usually come back within a few days.

What Happens If You Test Positive for Group B Strep?

If your test comes back positive, it means GBS bacteria were found in your body at the time of testing. This is really common—about 25% of pregnant people test positive.

Testing positive doesn’t mean you did anything wrong, that you have an infection needing treatment right now, or that your baby will definitely get sick.

What it does mean is that your healthcare team will recommend antibiotics (usually penicillin) through an IV during labor to protect your baby from GBS infection.

GBS Treatment During Labor: What to Expect

If you test positive for GBS, here’s what typically happens:

Antibiotics through an IV: When you arrive at the hospital or birth center in labor, you’ll receive antibiotics through an IV. The most common antibiotic is penicillin. If you’re allergic to penicillin, your provider will use a safe alternative.

Timing matters: Ideally, you’ll receive antibiotics at least 4 hours before your baby is born. You’ll get a dose when you first arrive in labor, and then additional doses every few hours until delivery.

It doesn’t have to change your birth plan: You can still move around, use a birth ball, and labor however feels right to you. Some facilities offer portable IV poles or saline locks between doses so you have more freedom to move. Your doula can support you in navigating movement in labor with an IV.

What If You Go Into Labor Early?

If you haven’t been tested yet because you’re not quite 36 weeks, your provider will likely treat you as GBS-positive and give you antibiotics during labor just to be safe. This is especially true if your water breaks before 37 weeks, you develop a fever during labor, or your water has been broken for 18 hours or more.

What About Planned Cesarean Birth?

If you’re having a scheduled cesarean birth and your water hasn’t broken and you’re not in labor, the risk of passing GBS to your baby is very low. Your provider may not recommend antibiotics for GBS, but every situation is different.

Can You Refuse Antibiotics for Group B Strep?

Yes—you always have the right to make informed decisions about your care.

If you’re considering declining antibiotics for GBS, it’s important to understand the risks: Without antibiotics, babies born to GBS-positive mothers have about a 1-2% chance of developing a GBS infection. With antibiotics, that risk drops to about 0.2-0.4% (CDC).

Have an honest conversation with your provider. Share your concerns and ask questions. Your healthcare team can help you understand the risks and benefits based on your specific situation.

Some people ask about natural remedies like garlic or probiotics. Current research doesn’t support these as effective alternatives to antibiotics for preventing GBS infection in newborns.

What Happens After Your Baby Is Born?

If you tested positive for GBS and received antibiotics during labor, your baby will be monitored more closely for the first 24-48 hours after birth. The healthcare team will watch for any signs of infection, such as difficulty breathing, fever, lethargy, or irritability.

Most babies do beautifully and show no signs of infection. If your baby does develop symptoms, they’ll be evaluated and may receive antibiotics as a precaution.

Questions to Ask Your Provider

Here are some questions that can help you feel more informed:

When will I be tested for Group B Strep?
If I test positive, what antibiotics would you recommend?
Can I still labor in water or move freely with an IV?
What happens if I go into labor before I’m tested?
What will monitoring look like for my baby after birth?
What are my options if I want to decline antibiotics?

How Your Doula Can Support You

Your doula is there to support you through all of this. They can help you prepare questions for your healthcare provider, talk through any concerns about testing positive, support you in making informed decisions, help you stay comfortable during labor even with an IV, and advocate for your preferences.

Remember, your doula is there to support you and help you feel informed, heard, and empowered.

The Bottom Line

Group B Strep is common, and testing positive doesn’t mean you’ve done anything wrong. With antibiotics during labor, the risk to your baby is very small. Your healthcare team will work with you to keep you and your baby safe and healthy.

If you have questions or concerns about GBS testing or treatment, bring them to your next prenatal appointment. You deserve to understand what’s happening and feel confident in the choices you make for your birth.

You’re doing an amazing job caring for yourself and your baby.

Need Support During Pregnancy and Birth?

A doula can help—and you may qualify for free.

A doula is a trusted support person you can talk with about pregnancy questions like Group B Strep testing. They can also help you prepare for your birth, support you during your labor and delivery, and help you once you are home with your new baby.

If you live in Linn, Benton, Lincoln, Lane, Marion, or Polk counties and have Medicaid/OHP, you are eligible for free doula care through the Community Doula Program.

Learn About Free Doula Care