Prenatal Testing

Group Beta Strep Testing (GBS)

Group B Strep is a normal intestinal bacteria that sometimes migrates from the digestive tract to the anal area. At 35-37 weeks pregnancy your midwife will ask you to test for Group B Strep. This involves taking a swab of the perineal area and allowing any bacteria to grow in a culture.

What you need to know

If you test positive for Group B Strep it means the bacteria is on your perineal area. You will be offered antibiotics during labor to ensure the bacteria does not get on your baby and cause an infection.

Some midwives allow women who test positive take antibiotics during pregnancy and do the test again to see if the infection is gone. Your ability to use this strategy will depend on how much time you have before the expected birth.


You will need to remove the clothing from your vaginal area, but may only need to lower your clothes or raise a skirt rather than strip down to an examination gown. Your midwife will make a quick rub around your vagina and rectum then send the swab off for culture. You will receive the results in a few days.

Jennifer (Author)