Group B Streptococcus (GBS)

GBS is a type of bacteria that can be found in 10-30% of pregnant women. It usually does not cause serious illness. It may be found in the digestive, urinary, and reproductive tracts of men and women. In women, it is most often found in the vagina and rectum. GBS is not a sexually transmitted disease.

A woman with GBS can pass it to her baby during delivery. Most babies who get GBS from their mothers do not have any problems. A few, however, will become sick. This can cause major health problems or even threaten their lives.

If the bacteria are passed from a woman to her baby, the baby may develop GBS infection. This happens to only 1 or 2 of every 100 babies whose mothers have GBS. Babies who do become infected may have early or late infections. Both early and late GBS infections lead to death in about 5% of infected babies.

A culture is the most accurate way to test for GBS. This is a simple painless procedure performed at 35 to 37 weeks. A swab is placed in the woman's vagina and rectum to obtain a sample. If the test results are positive, showing that GBS is present, you will receive antibiotics during labor to help prevent GBS from being passed to your baby.

Babies of women who are carriers of GBS and do not get treatment have more than 20 times the risk of getting infected than those who do receive treatment. The antibiotics work only if taken during labor. The bacteria grow so fast that if treatment is given earlier, the GBS may grow back before labor. If you had a previous baby with GBS infection or you had a urinary tract infection caused by GBS during pregnancy, you do not need to be tested. You will need to get antibiotics during labor.

In women who have planned a cesarean birth, it is not necessary for them to be given antibiotics during delivery, whether or not they are GBS carriers. However, these women should still be tested for GBS because preterm labor may occur before the planned cesarean birth and your baby's pediatrician will want to know the results.

GBS is fairly common in pregnant women. Yet, very few babies actually become sick from GBS infection. Treatment during labor and delivery may help prevent infection in your baby.

If you would like additional information about GBS, please ask for a brochure, and/or talk with you doctor or nurse practitioner.