You went to your 36 week prenatal appointment and received a swab test for GBS. You may not have thought anything of it until your provider’s office called with the results that you tested positive for GBS. What does it mean if you tested positive for GBS?
Let’s begin with what is. GBS (Group B Streptococcus) is a type of bacteria often found in the urinary tract, digestive system, and reproductive tracts. GBS usually comes and goes from our bodies and most women don’t realize they have this type of bacteria because typically healthy adults do not show any symptoms. However, GBS is technically contagious and can be passed to the newborn baby via birth.
Because this bacteria has almost no symptoms in the pregnant person, but does have risk for severe illness to the baby, each pregnant woman will be offered to be tested around 36 weeks of pregnancy. If your results are negative, nothing changes. If found positive, or you decline the test, your provider will likely highly recommend you have IV (Intravenous) antibiotics during labor to help the bacteria die down to safe levels and not pass on to your baby as she/he passes through the birth canal. The antibiotics only last for four hours. This means that you more than likely will have repeated doses of the IV antibiotics during labor.

The good thing is, the antibiotics do not have to be continuously dripped. It’s given in doses and then the IV can be unhooked and you would not need to have any more antibiotics until four hours later. The first dose takes the longest to be administered (around 45-60 minutes) while any subsequent doses take about 20 minutes to be administered. You will be given doses every four hours until your baby is born.
A baby whose mom tested positive for GBS bacteria and was able to receive the antibiotics during labor has only a 1 in 4000 chance of the baby having any symptoms for GBS, while a baby whose mom wasn’t able to receive antibiotics, has a 1 in 200 chance of developing symptoms. The risk of serious infection for a baby whose mom received antibiotics is .02% while a baby whose mother did not receive antibiotics has around 1%-2% risk.
If you have tested positive for GBS bacteria and you end up needing a cesarean birth and your water never breaks, you do not need the antibiotics.
If you have any questions about the testing or your own results, we always recommend having an open discussion with your doctor or midwife.