Abstract
Objective This study aimed to assess whether colonization with group B streptococcus (GBS)
is associated with maternal peripartum infection in an era of routine prophylaxis.
Study Design This study presented a secondary analysis of women delivering ≥37 weeks who underwent
a trial of labor from the U.S. Consortium on Safe Labor (CSL) study. The exposure
was maternal GBS colonization and the outcome was a diagnosis of chorioamnionitis,
and secondarily, analyses were restricted to deliveries not admitted in labor and
measures of postpartum infection (postpartum fever, endometritis, and surgical site
infection). Logistic regression with generalized estimating equations was used accounting
for within-woman correlations. Models adjusted for maternal age, parity, race, prepregnancy
body mass index, pregestational diabetes, insurance status, study site/region, year
of delivery, number of vaginal exams from admission to delivery, and time (in hours)
from admission to delivery.
Results Among 170,804 assessed women, 33,877 (19.8%) were colonized with GBS and 5,172 (3.0%)
were diagnosed with chorioamnionitis. While the frequency of GBS colonization did
not vary by chorioamnionitis status (3.0% in both groups), in multivariable analyses,
GBS colonization was associated with slightly lower odds of chorioamnionitis (adjusted
odds ratio [AOR]: 0.89; 95% confidence interval [CI]: 0.83–0.96). In secondary analyses,
this association held regardless of spontaneous labor on admission; and the odds of
postpartum infectious outcomes were not higher with GBS colonization.
Conclusion In contrast to historical data, GBS colonization was associated with lower odds of
chorioamnionitis in an era of routine GBS screening and prophylaxis.
Key Points
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Data in an era prior to routine group B streptococcus (GBS) screening and prophylaxis
showed that maternal GBS colonization was associated with a higher frequency of maternal
peripartum infection.
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In the current study, GBS colonization was associated with lower odds of chorioamnionitis
in an era of routine GBS screening and prophylaxis.
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The results highlight potential benefits of GBS screening and intrapartum antibiotic
prophylaxis beyond neonatal disease prevention, including mitigating the risk of maternal
infectious morbidity.
Keywords
pregnancy - GBS colonization - chorioamnionitis - peripartum infection
