Test for group B strep

Expect to be screened for group B streptococcus (GBS) during the third trimester. GBS is a common bacterium often carried in the intestines or lower genital tract that's usually harmless in adults. But babies who become infected with GBS from exposure during vaginal delivery can become seriously ill.

To screen for GBS, your health care provider will swab your lower vagina and anal area. The sample will be sent to a lab for testing. If the sample tests positive for GBS — or you previously gave birth to a baby who developed GBS disease — you'll be given intravenous antibiotics during labor. The antibiotics will help protect your baby from the bacterium.