Impact of vaginal ascorbic acid on abnormal vaginal microflora

Purpose: To evaluate the impact of vaginal ascorbic acid (vitamin C) as a treatment/maintenance regimen on increased vaginal pH and abnormal microflora on wet mounts in premenopausal women. Methods: A randomized study of 140 asymptomatic, low-risk pregnant and non-pregnant premenopausal women with vaginal pH ≥ 4.5 and a variety of partly/completely disrupted Lactobacillus microflora patterns on wet mounts in five outpatient clinics was carried out. Participants were randomized to the intervention group [250 mg vitamin C tablets vaginally at bedtime once a day for 6 days (treatment phase), followed by a one tablet per week, for 12 weeks (maintenance phase)] or the control group (no treatment). Outcomes were evaluated 4 months after randomizing, i.e., 2-3 weeks after the last vitamin C tablet insertion. Results: Normalization to normal flora was observed in 51.4 % of all ascorbic acid and in 24.3 % of control group patients (difference 27.1 %, 95 % CI 11.7-42.6, p < 0.05, ITT population). In the per protocol population, normalization was confirmed in 53.5 % of the intervention and 22.4 % of the control group (difference 31 %, 95 % CI 14.3-47.8, p < 0.05). Results of pregnant subgroup analysis showed better outcomes for the subgroup: difference of normalization rate between ascorbic acid and control group was 41.2 % (95 % CI 21.8-60.1, p < 0.05). Itching occurred in 19 %; 23 % of women reported irritation and 10 % stopped the treatment because of side effects. Conclusions: Vaginal ascorbic acid improves abnormal vaginal pH and microflora, especially in pregnant women, but is not well tolerated by all women.