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What is Group B Strep and why does my provider want to test for it?

Group B strep (GBS) is one of many bacteria that live in the body of healthy people without causing harm. It is present in the intestine, rectum, and vagina of about 20 percent of all women near the time of birth. GBS is not a sexually transmitted infection (STI) and does not have any vaginal symptoms. Because of where it is found, it may be passed on during labor from mother to baby.

GBS can cause newborn infections in the blood, lungs, or inflammation of the covering of a baby’s brain or spinal cord. Full-term babies whose mothers carry GBS in the vagina or rectum during labor and birth have a 1 in 200 chance of getting sick. It is also possible for mother’s to develop a uterine infection if these bacteria are present during their labor.

Even though the risk for these infections is low, the disease can cause significant harm to your baby if untreated. The good news is that this infection can be prevented. During a prenatal visit between 35-37 weeks in your pregnancy, your provider will offer you a screening test for GBS. A Q-tip is used to collect a sample by touching the vagina and just inside the rectum to obtain a culture. If the test is positive it will be noted on your medical record and the hospital or birth center will be aware of this when you present in labor.

The best time to treat GBS is while you are in labor. The most common drug used to treat GBS is Penicillin but if you are allergic to Penicillin, there are other options that your provider can use.

In order to prevent this infection, there are other times that the Center for Disease Control (CDC) recommends treatment without testing. These times are listed below:

Dr. Cheryl Sharp, Chief Content Officer
Cheryl is a midwife and women's health nurse practitioner who has been caring for women, newborns, and families more than 30 years. She views the opportunity to journey with women through their pregnancy and beyond as a sacred privilege.