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.