Prenatal screening for Group B streptococci often fails to live up to current screening and treatment guidelines
Research Activities, February 2011, No. 366
Nearly one in four pregnant women carry Group B streptococci (GBS). This is a usually harmless bacteria in adults, but can cause life-threatening blood infection, meningitis, or pneumonia in newborns when passed during childbirth. In 2002 the Centers for Disease Control and Prevention (CDC) issued guidelines recommending that pregnant women be screened for GBS between weeks 35 and 37 of their pregnancies. If results are positive, mothers should receive intravenous antibiotics 4 or more hours before delivering to prevent passing GBS to the baby. A new study shows that while 85 percent of women in Tennessee were screened for GBS, the test was often performed too early and not every woman who tested positive for GBS received antibiotics before delivery.
Using a random sample of 877 live births in 11 Tennessee counties during 2003 and 2004, the researchers found that 26 percent of women were tested for GBS before week 35. Early screening may indicate that providers are unfamiliar with the CDC guidelines, the authors suggest. Further, of the 27 percent of women who screened positive for GBS, 39 percent did not receive the recommended antibiotics before giving birth. Unfortunately, of the 40 cases of GBS identified during 2003 and 2004 in Tennessee, 21 cases (53 percent) occurred in babies whose mothers had not tested positive for GBS.
These cases may be a result of screening too early, improper specimen collection, or false-negative tests, the authors suggest. Additionally, 10 of the babies infected with GBS were born to mothers who were screened on time and received antibiotics before giving birth. The authors suggest that additional prevention strategies, such as vaccines, be considered if this trend becomes evident through other studies. This study was funded in part by the Agency for Healthcare Research and Quality (HS13833).
See "Adherence to perinatal group B streptococcal prevention guidelines," by William P. Goins, M.D., M.P.H., Thomas R. Talbot, M.D., M.P.H., William Schaffner, M.D., and others in the June 2010 Obstetrics and Gynecology 115(6), pp. 1217-1224.