Efficacy of an acidic vaginal gel on vaginal pH and interleukin-6 levels in low-risk pregnant women: a double-blind, randomized placebo-controlled trial

BACKGROUND: Increased interleukin-6 (IL-6) levels and a vaginal pH of > 4.7 are associated with obstetric complications such as preterm delivery and low birth weight. Topical treatments, able to maintain a physiological vaginal pH, could help in the prevention of vaginal infections. STUDY AIM: In a randomized, double-blind, placebo-controlled trial, we evaluated the effects of an acidic buffering vaginal gel (Miphil) on vaginal pH and IL-6 levels in pregnant women. PATIENTS AND METHODS: Seventy low-risk women pregnant with a singleton (second trimester) were enrolled in the trial. Thirty-five were randomized to the acidic gel, 2.5 g every 3 days for 12 weeks, and 35 to the corresponding placebo. Vaginal pH and vaginal IL-6 level were measured at baseline and after 12 weeks. Women were then followed until delivery. The main outcome measures were vaginal pH, vaginal pH normalization (pH < 4.5) and vaginal IL-6 levels. RESULTS: Vaginal pH at baseline was 4.6 +/- 0.4 and 4.4 +/- 0.3 in the acidic gel and the placebo group, respectively. At baseline, a total of 40% (14/35) and 22% (8/35) of women in each group, respectively, had a vaginal pH of > or = 4.7. At week 12, the vaginal pH was 4.3 +/- 0.3 in the acidic gel group and 4.3 +/- 0.3 in the placebo group (NS). The acidic gel normalized the vaginal pH in ten out of 14 women (p = 0.04) in comparison with only one out of eight women in the placebo group (NS). The acidic gel induced a significant (p < 0.02) reduction of vaginal IL-6 from 12.0 +/- 7 to 8.9 +/- 5 pg/l (-36%). In the placebo group, IL-6 increased from 9.0 +/- 5 to 13.5 +/- 6.8 pg/l (+50%) (p = 0.05). Birth weight was 2978 +/- 700 g in the placebo group and 3241 +/- 477 g in the acidic gel group (p = 0.06). CONCLUSIONS: The use of the acidic gel in low-risk pregnant women is able to maintain a physiological vaginal ecosystem and prevents the increases of vaginal pH and vaginal IL-6. Prospective and controlled trials are warranted to evaluate whether this acidic gel can reduce obstetric complications linked to vaginal inflammation during pregnancy.