Relationship between maternal group B streptococcal colonization and pregnancy outcome

Area of Science:

• Obstetrics and Gynecology
• Maternal-Fetal Medicine
• Microbiology

Background:

• Group B Streptococcus (GBS) is a common bacterium that can colonize the vagina.
• The role of GBS colonization in adverse pregnancy outcomes like preterm labor and premature rupture of membranes (PROM) requires further investigation.
• Vaginal microbiome composition, including lactobacilli and bacterial vaginosis-associated bacteria, may influence pregnancy outcomes.

Purpose of the Study:

• To investigate the association between maternal GBS colonization and the incidence of preterm labor.
• To examine the relationship between GBS colonization and premature rupture of membranes (PROM).
• To explore the prevalence of GBS in relation to vaginal flora composition.

Main Methods:

• Vaginal cultures were performed on 615 pregnant women at 22-26 weeks gestation and upon admission for delivery.
• Women with GBS-positive cultures did not receive antenatal antibiotics.
• Statistical analyses included Fisher exact test and maximum likelihood analysis.

Main Results:

• No significant difference in preterm labor or PROM rates was observed between GBS-positive and GBS-negative women.
• Maximum likelihood analyses identified known risk factors as significant predictors of preterm labor (OR: 6.48), but GBS colonization was not.
• Lactobacilli-reduced flora was more prevalent in GBS-positive women (14.3%) compared to GBS-negative women (6.4%).

Conclusions:

• Maternal GBS colonization is not associated with preterm labor or PROM in this obstetric population.
• This finding holds true even in the presence of lactobacilli-reduced vaginal flora in GBS-positive women.
• The low incidence of bacterial vaginosis-associated bacteria in the study population may be a relevant factor.