What is group B strep?

According to MedicineNet, group B strep is a bacteria found in the small and large intestine, the rectum and the vagina of up to 45 percent of healthy women. The bacteria usually does not cause any infection, and many people are not aware they are colonized by the bacteria.

MedicineNet states that a woman can pass group B strep to her baby before and during delivery, and it can be a dangerous infection in newborns. For this reason, pregnant women are tested for the bacteria prior to giving birth. Pregnant women who test positive for the bacteria receive a course of antibiotics before giving birth to prevent their newborn from contracting the bacteria.