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Group B Strep Prevention (GBS, baby strep, Group B streptococcal bacteria)

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Guidelines for GBS: Summary


The incidence of group B streptococcal disease in babies less than a week old declined by over 70% in the 1990s, coinciding with increased use of intrapartum antibiotic prophylaxis. In 1999, three years after the release of CDC guidelines in 1996, the incidence began to plateau. Studies conducted after the issuance of the 1996 guidelines prompted re-evaluation of prevention strategies by CDC. Compelling evidence for a strong protective effect of the screening-based strategy relative to the risk-based strategy led to a new recommendation in 2002 for universal prenatal screening for group B strep colonization by vaginal-rectal culture at 35-37 weeks gestation. In light of emerging clindamycin and erythromycin-resistant group B strep isolates, second line agents for penicillin-allergic women were revised. A number of additional issues related to management of threatened preterm delivery, planned cesarean section deliveries in group B strep colonized women, group B strep bacteriuria, management of newborns exposed to intrapartum chemoprophylaxis and culture collection and processing methods are also addressed. The 2002 guidelines for perinatal group B strep prevention are comprehensive and replace the 1996 guidelines.

The main differences and similarities between the 2002 revised and previous 1996 guidelines:


  • Recommendation of universal prenatal screening for vaginal and rectal group B strep colonization of all pregnant women at 35-37 weeks’ gestation

  • Updated prophylaxis regimens for women with penicillin allergy

  • Detailed instruction on prenatal specimen collection and expanded methods of group B strep culture processing, including instructions on susceptibility testing

  • Recommendation against routine intrapartum antibiotic prophylaxis for group B strep colonized women undergoing planned cesarean deliveries without preceding labor or membrane rupture

  • A suggested algorithm for management of patients with threatened preterm delivery

  • An updated algorithm for management of newborns exposed to intrapartum antibiotic prophylaxis

Although some important changes have been instituted, many recommendations remain the same:

  • Penicillin remains the first line agent for intrapartum antibiotic prophylaxis, with ampicillin an acceptable alternative

  • Women whose culture results are unknown at the time of delivery should be managed according to the risk-based approach; the obstetric risk factors remain unchanged (i.e., <37 weeks’ gestation, duration of membrane rupture >18 hours, or temperature >100.4 F (>38.0 C))

  • Women with negative vaginal and rectal group B strep screening cultures within 5 weeks of delivery do not require intrapartum antimicrobial prophylaxis for group B strep, even if they develop obstetric risk factors (i.e., <37 weeks’ gestation, duration of membrane rupture >18 hours, or temperature >100.4 F (>38.0 C))

  • Women with group B strep bacteriuria in any concentration during their current pregnancy or who previously gave birth to an infant with early-onset group B strep disease should receive intrapartum antimicrobial prophylaxis

Review complete guidelines:

2002 Revised Guidelines for Prevention of Perinatal Group B Streptococcal Disease

Take a look at the abstract of the paper that was the basis of the universal screening decision:

Schrag et al. (2002) A Population-Based Comparison of Strategies to Prevent Early-Onset Group B Streptococcal Disease in Neonates. New England Journal of Medicine. 347 (4): 233-239


Page Last Modified: April 20, 2008
Content Last Reviewed: April 20, 2008
Content Source: National Center for Immunization and Respiratory Diseases
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