Changes in the vaginal microbiota associated with primary ovarian failure Original paper

What was studied?

This study examined the vaginal microbiota and primary ovarian failure, using high-throughput 16S rRNA sequencing to characterize microbial shifts associated with ovarian dysfunction. The researchers compared vaginal microbial diversity, taxonomic composition, and predicted functional pathways across women with primary ovarian failure (POF), healthy reproductive-age controls, and a reference group of menopausal women. Through detailed microbial profiling, hormonal correlations, and machine-learning prediction modeling, the study evaluated how specific bacterial genera—particularly Lactobacillus species—associate with reproductive hormones such as FSH, LH, estradiol (E2), AMH, and prolactin. Visual data throughout the paper, including the alpha and beta diversity plots, clearly illustrate the increased richness and altered clustering of the POF-associated microbiome.

Who was studied?

The research analyzed vaginal samples from 22 women with POF, 29 healthy controls, and 50 menopausal women. Participants with POF were aged 20–40, experiencing amenorrhea and elevated FSH despite hormone replacement therapy. Controls had normal menstrual cycles and hormone profiles, while menopausal women had at least one year since last menstruation. Clinical characteristics show similar age, BMI, and waist-to-hip ratio across reproductive-age groups, but markedly higher FSH and LH and lower estradiol and AMH in POF, confirming clear endocrine disruption.

Most important findings

The vaginal microbiota in POF showed significantly increased diversity and reduced Lactobacillus dominance, as demonstrated in the alpha diversity plots and weighted UniFrac. Women with POF exhibited an enrichment of anaerobic genera such as Gardnerella, Prevotella, Bacteroides, Sneathia, Dialister, and Anaerococcus, while healthy controls were strongly dominated by Lactobacillus, particularly L. gallinarum and L. iners. A key observation was the species-level shift: POF samples had a decrease in L. gallinarum and an increase in L. iners, a pattern consistent with microbial instability. Hormonal correlations on page 8 showed Gardnerella and Prevotella positively associated with elevated FSH and LH, while Lactobacillus—especially L. gallinarum—positively correlated with E2 and AMH. Conversely, L. iners was negatively associated with estradiol and positively associated with prolactin, suggesting opposing biological roles of Lactobacillus species in ovarian function. Predictive modeling identified 34 genera capable of classifying POF with an AUC of 0.841, underscoring the strong discriminatory power of the vaginal microbial signature.

Comparison with menopausal women showed that although overall diversity was even higher in menopause, Lactobacillus abundance was lowest, revealing a continuum of microbiota deterioration paralleling ovarian insufficiency.

Key implications

The findings highlight a robust association between vaginal microbiota composition and ovarian endocrine status, suggesting microbial communities may influence or reflect ovarian aging and dysfunction. The contrasting effects of L. gallinarum (beneficial) and L. iners (potentially detrimental) introduce species-specific microbial signatures relevant to future diagnostic or probiotic interventions. This study strengthens the rationale for exploring targeted vaginal Lactobacillus–based therapeutics to modulate inflammation, support mitochondrial function, and potentially slow ovarian decline.

Citation

Wang J, Xu J, Han Q, et al. Changes in the vaginal microbiota associated with primary ovarian failure.BMC Microbiology. 2020;20:230. doi:10.1186/s12866-020-01918-0