Evaluation of the effects of probiotic supplementation on the ecology and inflammatory factors of female vaginal flora: a systematic review and meta-analysis

This meta-analysis systematically evaluated the effects of probiotic supplementation on vaginal microbiota and inflammatory factors in women. PubMed, Embase, Web of Science, CNKI, and Wanfang were searched from inception to January 2026 for randomized and controlled studies. Outcomes included vaginal pH, Nugent score, and inflammatory cytokines (IL-4, IL-6, IL-10, TNF-α). Fifteen studies were included. Compared with controls, probiotics did not significantly reduce IL-4, IL-6, IL-10, or TNFα levels, nor did they significantly improve Nugent score. However, probiotic supplementation significantly reduced vaginal pH (OR = 0.36, 95% CI: 0.15-0.89; P = 0.03), indicating improved maintenance of a weakly acidic vaginal environment. Sensitivity analyses showed generally stable results, although heterogeneity remained substantial for several outcomes. Overall, probiotics appear effective in modulating vaginal acid-base balance but show limited evidence for improving inflammatory cytokine profiles or restoring vaginal microbiota structure. Current data are insufficient to support routine probiotic use for optimizing vaginal microbiota and inflammatory status. Further high-quality, well-designed randomized controlled trials are required to clarify their clinical benefits.