Recurrence of Bacterial Vaginosis Is Significantly Associated With Posttreatment Sexual Activities and Hormonal Contraceptive Use

BACKGROUND: Bacterial vaginosis (BV) recurrence posttreatment is common. Our aim was to determine if behaviors were associated with BV recurrence in women in a randomized controlled trial (RCT). METHODS: Symptomatic 18- to 50-year-old females with BV (≥3 Amsel criteria and Nugent score NS = 4-10) were enrolled in a 3-arm randomized double-blind RCT Melbourne Sexual Health Centre, Australia, in 2009-2010. All 450 participants received oral metronidazole (7 days) and were equally randomized to vaginal clindamycin, lactobacillus-vaginal probiotic or vaginal placebo. At 1, 2, 3, and 6 months, participants self-collected vaginal smears and completed questionnaires. Primary endpoint was NS = 7-10. Cox regression was used to estimate hazard ratios (HRs) for risk of BV recurrence associated with baseline and longitudinal characteristics. RESULTS: Four hundred four (90%) women with postrandomization data contributed to analyses. Cumulative 6-month BV recurrence was 28% (95% confidence interval CI, 24%-33%) and not associated with treatment. After stratifying for treatment and adjusting for age and sex frequency, recurrence was associated with having the same pre-/posttreatment sexual partner (adjusted HR AHR = 1.9; 95% CI, 1.2-3.0), inconsistent condom use (AHR = 1.9; 95% CI, 1.0-3.3), and being non-Australian (AHR = 1.5; 95% CI, 1.0-2.1), and halved with use of an estrogen-containing contraceptive (AHR = 0.5; 95% CI, .3-.8). CONCLUSIONS: Risk of BV recurrence was increased with the same pre-/posttreatment sexual partner and inconsistent condom use, and halved with use of estrogen-containing contraceptives. Behavioral and contraceptive practices may modify the effectiveness of BV treatment. CLINICAL TRIALS REGISTRATION: ACTRN12607000350426.