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Updated: Jun 17, 2026
A Murine Model of Group B Streptococcus Vaginal Colonization
Published on: November 16, 2016
Timing of group B streptococcus screening in pregnancy: a systematic review
Arijaan W Valkenburg-van den Berg1, Rebecca L Houtman-Roelofsen, Paul M Oostvogel
1Department of Obstetrics and Gynecology, Haga Hospital/Juliana Children's Hospital, The Hague, The Netherlands. a.w.valkenburg@orange.nl
Insights
Screening pregnant women for Group B Streptococcus (GBS) at 35-37 weeks gestation is recommended. Late-pregnancy GBS cultures show high predictive value for delivery colonization, though some carriers may be missed.
Area of Science:
- Obstetrics and Gynecology
- Neonatal Health
- Infectious Disease Epidemiology
Background:
- Group B Streptococcus (GBS) is a major cause of neonatal sepsis.
- Current guidelines recommend antenatal GBS cultures at 35-37 weeks gestation and intrapartum antibiotic prophylaxis for positive cultures or preterm delivery.
- Optimizing antenatal culture effectiveness can further reduce early-onset GBS disease.
Purpose of the Study:
- To identify the optimal timing for antenatal GBS cultures.
- To enhance the prevention of perinatal GBS infections in both term and preterm neonates.
Main Methods:
- A systematic review of PubMed and EMBASE databases was conducted.
- Articles published from 1966 to February 2009 were included.
- Data on study characteristics and predictive values of antenatal GBS cultures were extracted from nine selected articles.
Main Results:
- Positive predictive values for antenatal GBS cultures ranged from 43% to 100% (mean 69%).
- Negative predictive values ranged from 80% to 100% (mean 94%).
- GBS cultures obtained in late pregnancy demonstrated high positive predictive values for colonization at delivery, with consistently high negative predictive values irrespective of gestational age.
Conclusions:
- The systematic review supports current recommendations for GBS screening at 35-37 weeks gestation.
- Awareness of screening limitations is crucial, as approximately 6% of GBS carriers may not be detected by antenatal cultures.
Background:
Group B streptococcus (GBS) is an important cause of neonatal sepsis. Guidelines advise to collect cultures at 35-37 weeks' gestation and to administer intrapartum antibiotic prophylaxis in case of GBS-positive cultures, as well as in all preterm deliveries. Improved effectiveness of antenatal cultures might help to further decrease GBS early-onset disease.
Objective:
To determine the best timing of antenatal cultures, which may help establish optimal prevention of perinatal GBS infection in both term and preterm neonates.
Methods:
PubMed and EMBASE databases were searched for relevant articles published from 1966 to February 2009. Nine articles were included. Information about study features and predictive values of antenatal cultures were abstracted.
Results:
Positive predictive values for antenatal GBS cultures ranged from 43 to 100% (mean 69%) and negative predictive values from 80 to 100% (mean 94%). GBS cultures collected in late pregnancy had high positive predictive values for colonization during delivery. The negative predictive value was high and relatively constant regardless of GA.
Conclusions:
This systematic review confirms recommendations to screen pregnant women for colonization of GBS at 35-37 weeks' gestation, but one should be aware of the limitations of screening, with 6% of GBS carriers remaining undetected in antenatal cultures.
