Group B Strep (GBS)
What the test means and why antibiotics during labor may be recommended
What GBS Is
Group B streptococcus is a type of bacteria that lives naturally in the vagina or rectum of about one in four adults. It is not a sexually transmitted infection and does not cause symptoms in the person who carries it. However, if a person carries GBS during labor, the bacteria can be passed to the baby during birth. In rare cases, this can cause a serious infection in the newborn.
Testing and Results
A GBS screening test is routinely done between 36 and 37 weeks of pregnancy. A swab is taken from the vagina and rectum and sent to a lab. If the result is positive, your partner will be offered intravenous antibiotics during labor to reduce the risk of passing the bacteria to the baby. If the result is negative, no antibiotics are needed. If labor starts before the test is done, the care team may recommend antibiotics based on risk factors.
What the Antibiotics Mean for Labor
If your partner tests positive, IV antibiotics will be started once labor is established or after the water breaks. The antibiotics are typically given every four hours until the baby is born. They require an IV line, which may limit movement slightly, but your partner can still use most positions and comfort measures. The antibiotics are safe for the baby and do not affect the baby's microbiome long-term.
What You Can Do
Help your partner remember when the next antibiotic dose is due or ask the nurse. If your partner is anxious about having an IV, remind them that the alternative, a newborn infection, is far more serious. Most people who carry GBS have healthy babies with no complications when antibiotics are given during labor.