Group B strep is a bacterial infection babies can get during delivery or in their first weeks of life. It can cause serious complications. Pregnant people are screened for group B strep during pregnancy. Antibiotics can treat the infection if you test positive.
Group B strep infection (also GBS or group B Streptococcus) is caused by bacteria typically found in a person's vagina or rectal area. About 25% of pregnant people have GBS, but don't know it because it doesn't cause symptoms. A pregnant person with GBS can pass the bacteria to their baby during vaginal delivery. Infants, older adults or people with a weakened or underdeveloped immune system are more likely to develop complications from group B strep.
Most newborns who get GBS don't become sick. However, the bacteria can cause severe and even life-threatening infections in a small percentage of newborns. Healthcare providers screen for group B strep as part of your routine prenatal care. If you test positive, your provider will treat you with antibiotics.
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GBS bacteria naturally occur in areas of your body like your intestines and genital and urinary tracts. Adults can't get it from person-to-person contact or from sharing food or drinks with an infected person. Experts aren't entirely sure why the bacteria spreads, but they know that it’s potentially harmful in babies and people with weakened immune systems.
The Centers for Disease Control and Prevention (CDC) recommends routine screening for group B strep in all pregnancies. You're screened for GBS between 36 and 37 weeks of pregnancy. Group B strep testing involves your provider taking a swab of your vagina and rectum and then sending it to a lab for analysis.
GBS doesn't affect the fetus baby while it's still inside your uterus. However, your baby can get GBS from you during labor and delivery. Taking antibiotics for GBS reduces your chances of passing it to your baby.
There are two main types of Group B strep in babies:
Group B strep screening during pregnancy has decreased the number of cases. According to the CDC, about 930 babies get early-onset GBS, and 1,050 get late-onset GBS. About 4% of babies who develop GBS will die from it.
Most adults don't experience symptoms of group B strep. It can cause symptoms in older people or people with certain medical conditions, but this is rare. These symptoms include:
Newborns with GBS have symptoms like:
Other people that live with you, including other children, aren't at risk of getting sick.
Yes, your healthcare provider will test you for GBS late in your pregnancy, around weeks 36 to 37.
Your obstetrician uses a cotton swab to obtain samples of cells from your vagina and rectum. This test doesn't hurt and takes less than a minute. Then, the sample is sent to a lab where it's analyzed for group B strep. Most people receive their results within 48 hours. A positive culture result means you're a GBS carrier, but it doesn't mean that you or your baby will become sick.
If you’re using a midwife, you might be given instructions on how to test yourself at home and submit the swab to a lab.
No, group B strep isn't an STI (sexually transmitted infection). The type of bacteria that causes GBS naturally lives in your vagina or rectum. It doesn't cause symptoms for most people.
Healthcare providers prevent GBS infection in your baby by treating you with intravenous (IV) antibiotics during labor and delivery. The most common antibiotic to treat group B strep is penicillin or ampicillin. Giving you an antibiotic at this time helps prevent the spread of GBS from you to your newborn. It's not effective to treat GBS earlier than at delivery. The antibiotics work best when given at least four hours before delivery. About 90% of infections are prevented with this type of treatment.
One exception to the timing of treatment is when GBS is detected in urine. When this is the case, oral antibiotic treatment begins when GBS is identified (regardless of the stage of pregnancy). Antibiotics should still be given through an IV during labor.
Any pregnant person who has previously given birth to a baby who developed a GBS infection or who has had a urinary tract infection in this pregnancy caused by GBS will also be treated during labor.
Some babies still get GBS infections despite testing and antibiotic treatment during labor. Healthcare providers might take a sample of the baby's blood or spinal fluid to see if the baby has GBS infection. If your baby has GBS, they're treated with antibiotics through an IV.
Anyone can get GBS. Some people are at higher risk due to certain medical conditions or age. The following factors increase your risk for having a baby born with group B strep:
Getting screened for GBS and taking antibiotics (if you're positive) is the best way to protect your baby from infection.
Infants with GBS can develop meningitis, pneumonia or sepsis. These illnesses can be life-threatening. Most infants don't develop any long-term issues; however, about 25% of babies with meningitis caused by GBS develop cerebral palsy, hearing problems, learning disabilities or seizures.
No, once you test positive for GBS, you're considered positive for the rest of your pregnancy. You will not get re-tested.
No, you don't need antibiotics if you're having a c-section delivery. However, you'll still be tested for GBS because labor could start before your scheduled c-section. If your water breaks and you're GBS positive, your baby is at risk of contracting the disease.
In some cases, GBS causes infections during pregnancy. Symptoms of infection include fever, pain and increased heart rate. Let your provider know if you have any of those symptoms as it could lead to preterm labor.
GBS can also cause urinary tract infection (UTI), which requires oral antibiotics.
Talk to your provider about what you can expect during labor and delivery if you have group B strep.
A note from Cleveland Clinic
Try not to panic if your healthcare provider tells you you're positive for group B strep during pregnancy. It's caused by bacteria that occur naturally in your body, not by anything you did wrong. The chances of you passing group B strep to your baby are quite low, especially if you take antibiotics during labor. Talk to your provider about group B strep and share any concerns you have. In most cases, testing positive for GBS causes no problems, and your baby is healthy.
Last reviewed by a Cleveland Clinic medical professional on 04/27/2022.
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