Prevalence and risk factors of bacterial vaginosis during the first trimester of pregnancy in a large French population-based study

ObjectivesBacterial vaginosis is a risk factor for preterm delivery. Its prevalence and risk factors in Europe are not well known. Our objective was to assess both in early pregnancy.Study designAs part of the PREMEVA randomized controlled trial, this population-based study included 14,193 women screened before 14 weeks’ gestation for bacterial vaginosis in the 160 laboratories of the Nord-Pas-de-Calais region in France. Bacterial vaginosis was defined by a Nugent score ≥ 7. Data were collected about maternal tobacco use, age, education, and history of preterm birth. We estimated the prevalence of bacterial vaginosis and used a multilevel logistic regression model to identify significant risk factors for it.ResultsAmong the 14,193 women assessed before 14 weeks’ gestation, the prevalence of bacterial vaginosis was 7.1% (95% CI: 6.6–7.5%). In the multivariate analysis, smoking during pregnancy tobacco (adjusted OR: 1.38; 95% CI: 1.19–1.60), maternal age 18–19 years (adjusted OR: 1.40; 95% CI: 1.01–1.93), and educational level (completed only primary school: adjusted OR: 1.77; 95% CI: 1.35–2.31; completed only secondary school: adjusted OR: 1.27; 95% CI: 1.10–1.48) were independent risk factors for bacterial vaginosis. History of preterm delivery was not an independent risk factor of bacterial vaginosis: adjusted OR: 1.15; 95% CI: 0.90–1.47.ConclusionIn a large sample of women in their first trimester of pregnancy in France, the prevalence of bacterial vaginosis was lower than rates reported in other countries, but risk factors were similar: young age, low level of education, and tobacco use during pregnancy. These results should be considered in future strategies to reduce preterm delivery.