However, this bacteria usually does not cause genital symptoms or discomfort and is generally not linked with increased sexual activity. Therefore GBS is not considered to be a sexually transmitted disease. Why only certain infants fall victim to this infection is not completely known. An estimated 12,000 babies will suffer from GBS infections each year. Most often, GBS colonizes the baby during labor either by traveling upward from the mother's vagina into the uterus, or as the infant passes through the birth canal.
Illness occurs when the bacteria enters the baby's blood stream.
In certain cases, evidence exists that GBS may cross intact membranes to infect the baby in utero. All of these conditions are life threatening. GBS is also responsible for causing infections in nearly 50,000 pregnant women each year including fever after birth, uterine inflammation, and infections following cesarean sections. GBS can be present in a woman's first pregnancy, or in following pregnancies. The bacteria can be a threat both during pregnancy and at the time of delivery.