Group B strep (GBS) bacteria are usually harmless to healthy adults. But this type of bacteria in the intestines and lower genital tract can cause serious illness in newborns.

Babies can get GBS bacteria from their birthing parent during labor and delivery.

GBS can cause symptoms in infants that include lethargy, high fever, and difficulty breathing. Severe cases can be fatal and complications of GBS can be lifelong.

New parents can take steps to protect babies during pregnancy, labor, and delivery. If the birthing parent has GBS, transmission to the baby can be prevented by treating the birthing parent.

Group B Streptococcus is often referred to as group B strep or GBS. It’s a type of bacteria that’s often found in the human body, primarily in the gastrointestinal and genital tracts.

In most cases, GBS is harmless. However, these bacteria can cause serious infections known as GBS disease. This is especially dangerous for newborns and adults with other medical conditions.

About 1 and 4 women carry GBS bacteria during their pregnancy, according to the Centers for Disease Control and Prevention (CDC). The bacteria can pass to newborns during labor and delivery and cause severe illness.

Language matters

Sex and gender exist on spectrums. We may use “women” and “men” in this article to reflect the terms that have been historically used to gender people, especially in research. But your gender identity may not align with how your body responds to this disease. Your doctor can better help you understand how your specific circumstances will translate into diagnosis, symptoms, and treatment.

Without treatment, this infection caused by GBS can be fatal to newborns. The best way to address this is to keep doctor’s appointments and undergo lab testing and treatment as recommended.

GBS is a common bacteria. Anyone can develop GBS disease. However, some people have a higher risk than others. The risk factors of passing GBS to a newborn are different from the risk factors for developing GBS as an adult.

Factors that increase the risk of passing GBS to a newborn include:

  • developing a fever while in labor
  • testing positive for GBS late in your pregnancy
  • having labor that lasts 18 or more hours between when water breaks and when the baby is born

Factors that increase the risk of developing GBS as an adult include:

Doctors screen for GBS by taking samples of sterile body fluids. Sterile fluids include spinal fluid and blood.

The samples will be tested to see if GBS bacteria grow in them during a lab culture. This test can take a few days. Sometimes, additional tests, such as urinalysis, can also help screen for GBS.

A GBS infection can lead to serious complications. These infections can be fatal for newborns. In the United States, about 4% to 6% of all babies who develop GBS will die.

There can also have lingering effects in children who’ve already been treated successfully. Babies who have GBS are at risk for long-term complications, such as developmental disabilities and deafness.

Additionally, GBS might be linked to difficult pregnancies and could cause a range of complications, including miscarriages and stillbirths. However, this is not a direct and proven link.

There are guidelines that help prevent GBS transmission to babies.

Guidance from The American College of Obstetricians and Gynecologists (ACOG) and the American College of Nurse-Midwives (ACNM) recommends that everyone who is pregnant get tested for GBS bacteria when they’re between 36 and 37 weeks pregnant. This test is done by swabbing the vagina and rectum.

People who test positive for GBS are at an increased risk of passing GBS to their newborn if they do not get antibiotics during labor, according to the CDC.

Keep in mind, it’s very common for people to carry GBS bacteria in their bodies without having any symptoms. That’s why having a test is so important.

GBS bacteria that’s harmless to the birthing parent’s body can put the newborn in danger. Having test results is vital and allows for increased precautions.

Antibiotics are given during pregnancy to people who are at an increased risk of passing GBS on to their newborns. Antibiotics can protect babies and prevent GBS transmission.

However, antibiotics have to be given during labor. Antibiotics taken before labor won’t protect the baby because the bacteria will grow back.

An antibiotic called beta-lactam is used most often and is delivered by IV. Beta-lactam is a combination of penicillin and ampicillin. People who are allergic to either of those antibiotics can receive a different antibiotic.

It’s safe to receive antibiotics during labor. According to the CDC, about 1 in 10 people who are pregnant experience mild side effects from receiving penicillin, such as bloating or nausea.

Severe allergic responses that require medical treatment are possible but rare. The CDC says that they affect about 1 in every 10,000 pregnant people.

There’s currently no vaccine to prevent GBS and protect newborns.

However, several research groups are working to change this. The World Health Organization (WHO) has said that developing vaccines for GBS is an urgent need.

There are currently multiple vaccines in trial stages, and several have shown promising results in early research. While none of these vaccines have yet been approved and made available, it’s likely that one will be in the future.

Group B strep is a type of bacteria found in the human body. It primarily lives in the digestive and genital tracts, and is normally harmless.

However, GBS can cause serious and even fatal infections. The bacteria is especially dangerous to newborns and can be passed from birthing parents to children during labor and delivery.

Testing late in pregnancy is done to help protect newborns and prevent serious infection. If a birthing parent tests positive for GBS, antibiotics given during labor can stop GBS from being transmitted to the baby.