Routine testing for group B streptococcus in pregnancy: protocol for a UK cluster randomised trial (GBS3)

Area of Science:

• Obstetrics and Gynecology
• Neonatal Medicine
• Infectious Diseases

Background:

• Group B Streptococcus (GBS) is a leading cause of early-onset neonatal sepsis.
• Current strategies for GBS screening in pregnancy vary, with unclear benefits.
• A comparative effectiveness study is needed to determine optimal GBS screening protocols.

Purpose of the Study:

• To compare the effectiveness of routine GBS testing versus a risk factor-based strategy in reducing early-onset neonatal sepsis.
• To evaluate the cost-effectiveness of antenatal enriched culture medium testing versus intrapartum rapid testing for GBS.
• To assess the implementation and acceptability of different GBS screening strategies in maternity units.

Main Methods:

• A large-scale cluster randomized trial involving up to 320,000 women across 80 maternity units.
• Sites randomized to either routine GBS testing or risk factor-based strategy.
• Routine testing sites further randomized to antenatal or intrapartum testing, with intrapartum antibiotic prophylaxis for positive GBS or identified risk factors.

Main Results:

• The primary outcome is all-cause early neonatal sepsis (<7 days), defined by culture, death, or clinical signs with antibiotic treatment.
• Cost-effectiveness will be analyzed in terms of incremental cost per case of sepsis avoided and per quality-adjusted life-year.
• Data will be collected from routinely collected NHS databases and supplemented with process outcomes.

Conclusions:

• The trial aims to provide evidence on the most effective and cost-effective strategy for GBS screening to prevent neonatal sepsis.
• Findings will inform clinical practice guidelines and healthcare policy regarding GBS management in pregnancy.
• The study will also yield valuable economic, qualitative, and implementation data for health technology assessment.