Efficacy of vitamin C vaginal tablets as prophylaxis for recurrent bacterial vaginosis: a randomised, double-blind, placebo-controlled clinical trial.

Background: The aetiology of bacterial vaginosis (BV) is still unclear but it is currently considered to be a synergistic polymicrobial syndrome. BV can often arise as a chronic or recurrent disease. The reason for such recurrences is not well elucidated. Previous studies have suggested that vaginal vitamin C may be a useful treatment in reducing recurrence rate, by increasing vaginal acidification and thereby making up for the decrease in hydrogen peroxide that results from a reduction in the number of lactobacilli present. Based on the above-mentioned consideration, a study was performed that aimed to evaluate the effect of vitamin C in the prophylaxis of BV relapses.
Methods: This was a randomised, double-blind, placebo-controlled, parallel-group clinical trial. One hundred and forty-two women, after having been cured from a recent episode of BV by either metronidazole or clindamycin, were randomised to receive vitamin C (74 patients) or placebo (68 patients) as prophylaxis for six monthly cycles, starting within 24 hours of the determination of 'BV cure'. The patients applied one vaginal tablet once a day for 6 consecutive days per month after menses.
Results: The rate of BV recurrence during the first 3 months was considerably lower in the vitamin C group (6.8%) than in the placebo (14.7%) group. Considering a 6-month treatment period, the recurrence rate in the vitamin C group (16.2%) was significantly lower (P = 0.024) than in the placebo group (32.4%). Moreover, at the same time point, the survival analysis of Kaplan Meyer was significant in favour of the vitamin C group compared with the placebo group (P = 0.029).
Conclusions: The study showed that regular use of 250 mg ascorbic acid vaginal tablets on 6 days per month for 6 months after successful treatment of bacterial vaginosis halves the risk of recurrence from 32.4% to 16.2% (P = 0.024).