Effects of a 10-Strain Oral Probiotic on Parameters of Vaginal Health and Microbial Community: A Pilot Clinical Study

Abstract

Objective: To investigate the clinical effects of a 10-strain probiotic on parameters of vaginal health in a pilot, open label study in women with intermediate Nugent score (NS) or vaginal pH >4.5.

Methodology: A total of 43 healthy premenopausal women, ages 18 to 50 years, with NS of 4-6 or vaginal pH >4.5 were enrolled. Participants consumed a probiotic formulation (Feminine Support™), containing 8 lactobacilli and 2 bifidobacteria strains, with a daily dose of 2.5×10¹⁰ CFU for 28 (subgroup 1) or 42 (subgroup 2) days. Investigational visits occurred at day 0, 14, 28 and 42 with assessment of vaginal pH, NS and vaginal microbiota, via next-generation sequencing.

Results: A total of 36 participants were included in the analysis set, with 24 and 12 participants included in subgroups 1 and 2, respectively. In the analysis set, there was a significant reduction in vaginal pH, from baseline, at day 28 (mean change=-0.19, P = 0.047). Participants in subgroup 1 achieved a significant reduction in vaginal pH from baseline, at day 28 (mean change=-0.23, P = 0.029) and day 42 (mean change=-0.29, P = 0.008), while participants in subgroup 2 achieved a significant and quantitatively greater reduction in vaginal pH from baseline to day 42 (mean change=-0.64, P = 0.008). No significant changes in NS were reported, due in part to highly diverse baseline levels. Vaginal microbial abundance exhibited a majority lactobacilli abundance at baseline, which was maintained over the study period. Vaginal pH was inversely associated with lactobacilli abundance throughout the study (P < 0.005). The product was well tolerated with high compliance. Two participants reported adverse events with suspected causality, which were mild and resolved during the study.

Conclusion: This 10-strain probiotic formulation was well tolerated and helped reduce vaginal pH in women with intermediate NS or elevated vaginal pH. The study product warrants a randomized controlled trial to further assess efficacy.

Keywords: Nugent score; microbiome; probiotic; vaginal microbiota; vaginal pH.

Figure 1

Study design.

Figure 2

Participant flow-chart.

Figure 3

% of participants with vaginal pH ≤ 4.5 at each study visit. Intragroup comparison at Day 14, 28 and 42 as compared to Day 0 via McNemar test; *P < 0.05, **P < 0.01.