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GBS (Group B Streptococcus)

Group B Streptococcus (GBS) is the number one cause of life threatening infections, such as sepsis and meningitis, in newborn babies, and is also a frequent cause of newborn pneumonia. GBS infects approximately 8,000 infants in the Unites States each year, kills 2,000 annually, and leaves many others mentally and/or physically handicapped.

The GBS bacteria live in the gastrointestinal system and are found in the vagina or rectum of 15 to 40 percent of healthy, adult women. It’s not clear how women become infected with the bacteria and many women never experience any symptoms. However, untreated GBS can cause bladder infections, womb infections, and stillbirth. People with GBS usually carry the bacteria temporarily and do not become lifelong carriers.

Pregnant women are routinely tested for the bacteria late in pregnancy (35-37 weeks). The simple test involves swabbing the vagina and rectum for a sample of cells that are sent to a lab to look for GBS. Samples tested earlier than 35 weeks do not accurately predict whether the mother will have GBS at delivery.

Usually, babies are infected with GBS during delivery when they come into direct contact with the bacteria in the birth canal. However, only one out of every 100 to 200 babies whose mothers carry GBS develops the disease. Premature babies are more susceptible to GBS infection than full-term babies. Most babies who do contract the disease do so in the first hours or week of life, which is referred to as “early-onset disease.” The disease may also develop in infants up to several months after birth, called “late-onset disease,“ although this is rare. Only about 50 percent of late-onset GBS disease among newborns comes from a mother who is a GBS carrier; the source of infection for others with late-onset GBS disease is unknown. Delivering by c-section does not eliminate the risk of infection.

If a pregnant woman is diagnosed as carrying the GBS bacteria in her vagina or rectum, antibiotics should be given to her during labor. Administering antibiotics at the time of diagnosis may reduce the amount of GBS bacteria temporarily, but it will not eliminate it completely and will leave the baby unprotected during birth. However, if the GBS bacteria are present only in a pregnant woman’s urine, she should be treated with antibiotics at the time of diagnosis.

Some pregnant women are more likely to having a baby with GBS disease, including those:

• Who have had a previous baby with GBS disease


• Who have a urinary tract infection due to GBS


• Who carry GBS late in pregnancy


• Who have a fever during labor


• Whose membranes rupture 18 hours or more before delivery


• Who begin labor or whose membranes rupture before 37 weeks