by Schulte S

IMAGE Group B streptococcus (GBS) can cause serious illness or death in a newborn. You might not have heard of this disease. But if you are pregnant or thinking of getting pregnant, find out how a simple screening test and antibiotic treatment can protect you and your baby.

What Is GBS?

Group B strep is a bacterium that is commonly found in vaginal and/or rectal areas. GBS can sometimes cause illness in newborn babies, pregnant women, elderly adults, and adults with chronic medical conditions like diabetes, liver disease, and cancer.

This infection is generally easy to treat in adults. But, for newborn babies, it can lead to life-threatening infections, such as sepsis (blood infection) and rarely, meningitis (infection of the fluid and lining surrounding the brain). Babies who have had meningitis can develop long-term problems, such as hearing and/or vision loss or learning disabilities, and they can even die if the infection is left untreated.

Newborn babies become infected with GBS in 3 ways:

  • Before birth—Bacteria in the vagina can spread up the birth canal into the uterus and infect the amniotic fluid surrounding the baby. The baby becomes infected by inhaling the infected fluid into the lungs.
  • During birth—The baby can come in contact with the bacteria in the birth canal.
  • After birth—The baby can come in contact with the bacteria through close physical contact with the mother.

Fortunately, most babies who are exposed to the bacteria will not become infected.

How Do I Know If I’m at Risk?

GBS is present in about 25% of all healthy adult women. Not all women with the bacteria will pass it on. Factors that may increase your risk of passing GBS bacteria to your baby include:

  • A previous baby with GBS
  • GBS bacteria present in urine during any trimester of the current pregnancy
  • Positive GBS screening culture in third trimester of current pregnancy
  • Unknown GBS status and:
    • Labor or rupture of the membranes (water breaking) before 37 weeks gestation
    • A rupture of the membranes 18 hours or more before delivery
    • A fever during labor

What Are the Symptoms of GBS?

Usually, the pregnant woman has no symptoms of GBS. In pregnant women, GBS infections can cause infection of the uterine lining or amniotic fluid and can lead to a miscarriage. Two forms of infection occur in newborns.

Early-onset GBS

This produces illness soon after birth, usually within the first 24-48 hours, but may be up to 7 days. Problems can include sepsis, pneumonia, and meningitis.

Late-onset GBS

This usually occurs one week to three months after birth. Medical problems associated with late-onset disease may include sepsis and meningitis. There is a chance that infants with meningitis will have long-term problems, such as cerebral palsy, hearing loss, and developmental problems.

Newborns with GBS diseases can die if they do not receive treatment.


Symptoms for both early and late onset include:

  • Trouble breathing
  • Temperature instability (high and/or low)
  • Poor feeding
  • Irritability
  • Lethargy
  • Vomiting and diarrhea

If you notice any of these symptoms in your baby (especially if you have tested positive for GBS), call the doctor right away.

Getting Screened

Screening for GBS bacteria is simple. A swab of the of the vagina and rectum will be taken about one month before the baby is due. The sample will be sent to a lab to test for the presence of the bacteria. Test results are usually available in 24–48 hours.

What to Expect If Your Test Comes Back Positive

The most common treatment is to give IV antibiotics during labor, hopefully at least 4 hours prior to delivery. If your baby is diagnosed with GBS, IV antibiotics will also be given. In some cases, your baby may be given antibiotics as a preventive measure.

Using What You Know

The first thing you can do is make sure your doctor screens you for GBS before your delivery date at 35-37 weeks. If you have been identified as a GBS carrier, make sure to tell your doctor of your status when your water breaks or you arrive at the hospital in labor.

By getting screened and treated during labor (if you have GBS), you can reduce the risk of your child developing GBS.


Family Doctor—American Academy of Family Physicians 

The American Congress of Obstetricians and Gynecologists 


The Canadian Women's Health Network 

The Society of Obstetricians and Gynaecologists of Canada 


Group B strep infection: GBS. American Pregnancy Association website. Available at: Updated August 2015. Accessed June 30, 2016.

Group B streptococcal infection in infants less than 3 months old. EBSCO DynaMed website. Available at: Updated February 2, 2015. Accessed June 30, 2016.

Group B strep and pregnancy. The American College of Obstetrics and Gynecology website. Available at: Updated March 2015. Accessed June 30, 2016.

Group B strep infection in adults. Centers for Disease Control and Prevention website. Available at: Updated May 23, 2016. Accessed June 30, 2016.

Horsely L. CDC updates guidelines for the preventions of perinatal GBS disease. Am Fam Physician. 2011;83(9):1106-1110.

Meningitis. Nemours Kids Health website. Available at: Updated April 2016. Accessed June 30, 2016.

Routine prenatal care. EBSCO DynaMed website. Available at: Updated June 22, 2016. Accessed June 30, 2016.

Revision Information