35 week Group B Strep Screening

GBS screen

GBS (Group B streptococcus) is a very common bacterium that lives in the body. It is routinely found in the vagina or rectum of women and is not a sexually transmitted bacteria. Women who have the bacteria but are not sick are said to be “colonized.” This bacteria does not typically affect the mother, but it can be passed to the baby at the time of delivery. While most babies do not get sick from this, approximately 1 in 2000 babies born in the United States every year do and GBS infections cause death in approximately 5% of infected babies. Problems caused by infection with GBS can include pneumonia, sepsis (infection of the blood), and meningitis. Because these outcomes are so severe, we follow guidelines set forth by the CDC and screen routinely for GBS. If you have had a previous child who developed an infection with GBS, please tell your physician.

How do we test for GBS?

Late in pregnancy, around 35-37 weeks, we use a swab to swipe the outside of the vagina and rectum. The procedure is quick and is not painful. This swab is then sent to a lab and cultured. We usually receive the results in several days.

What do I do if the test is positive?

If the culture shows that GBS is present, you will receive IV antibiotics during labor. This helps to reduce the amount of bacteria present to decrease the risk or transmission of GBS to the baby.

Other situations that may require treatment during labor:

▪ If you had a previous baby who developed GBS infection

▪ If you had a urinary tract infection this pregnancy that showed GBS on culture

▪ If you have not had a GBS culture and any of the following:

▪ You go into labor at less than 37 weeks

▪ Your water has been broken for ≥18 hours during labor

▪ You have a fever ≥100.4 during labor

What if I am having a c-section?

Women who are undergoing a scheduled c-section, who do not go into labor, and whose water does not break do not typically require antibiotics before delivery for GBS prevention. However, because you can still go into labor or your water can break prior to the date of your c-section, we typically screen anyway.

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