Group B streptococcal bacteria (also called GBS or group B strep) is common and can be passed on to your baby during childbirth. whether you beget GBS,your baby can get very sick and even die whether you are not tested and treated. Ask your doctor for a GBS test when you are 35 to 37 weeks pregnant (in your 9th month). whether you test positive for it, your doctor can give you medicine during labor to retain it from spreading to your baby.
Source: cdc.gov