Screening for Group B Strep

Group B streptococcus (GBS) is a type of bacteria found in the bowel of up to 35 percent of healthy adults. In women, GBS can also be found in the vagina and bladder. Although similar in name, GBS is different from group A strep, the bacteria that causes "strep throat."


A person whose body carries GBS but shows no sign of infection is said to be "colonized." In certain circumstances, GBS can invade the body and cause a serious infection. Many of these infections occur in the elderly or in those with chronic medical conditions.


If a pregnant woman is colonized by GBS, she can pass it to her baby during childbirth. Most babies who get GBS from their mothers do not have any problems, but about 1-2 percent of babies per year born in the United States develop serious GBS disease. This includes sepsis (blood infections), meningitis (infection of the fluid and lining surrounding the brain) and pneumonia. Up to 5 percent of these babies die and those that survive may have long-term problems such as hearing and vision problems.


The Centers for Disease Control, American Academy of Pediatrics and American College of Obstetricians and Gynecologists recommend that all pregnant women be screened for GBS during pregnancy. A vaginal and rectal culture is performed around the 35th week of pregnancy. If the culture is positive, showing that GBS is present, the mother will receive intravenous antibiotics during labor to help prevent GBS from being passed to her baby.


Remember, although GBS is fairly common in pregnant women, very few babies actually get sick from a GBS infection. If you have any questions about GBS, please do not hesitate to ask at your next prenatal visit.