Targeted Vaginal Microbiome Modulation by Postbiotic Intervention Reduces Dysbiosis-Associated Pathogens in Infertile Women: A Pilot Study.

BACKGROUND

Vaginal dysbiosis characterized by depleted Lactobacillus populations is associated with impaired fertility outcomes in women undergoing assisted reproduction. Postbiotic interventions delivering antimicrobial peptides without live bacteria may offer targeted microecological modulation while preserving community stability. We investigated the microbial and clinical effects of an eight-week antimicrobial peptide-based postbiotic in infertile women.

METHODS

Fifteen infertile women (mean age 38.7 ± 4.1 years) with ≥ 2 prior in vitro fertilization failures received intravaginal postbiotic therapy (VAGINNE®, Good-Care Biotech, Ltd.) for 8.0 ± 0.3 weeks before frozen embryo transfer (FET). Paired vaginal samples collected pre- and post-treatment underwent full-length 16S rRNA gene sequencing using PacBio Sequel platform. Microbiome composition, beta-diversity, differential abundance, and absolute bacterial load were analyzed.

RESULTS

The cohort achieved a clinical pregnancy rate of 46.7% (7/15) following postbiotic intervention and subsequent FET. Beta-diversity analysis revealed preservation of global community structure (PERMANOVA R² = 0.05, p = 0.65), indicating ecological stability. Despite cohort-level stability, patient-specific analysis identified favorable microbiome restructuring in 73% of participants (11/15), including emergence of Lactobacillus-dominant communities in previously dysbiotic profiles. Absolute abundance quantification demonstrated selective elimination of dysbiosis-associated pathogens: Prevotella decreased from 408.47±990.78 to 0.29±0.83 cells/sample (p < 0.01), Pseudomonas from 419.07±567.04 to 89.14±114.42 (p < 0.05), and complete clearance of Howardella (3.53±9.87 to undetectable). Conversely, Gluconacetobacter increased significantly from undetectable to 2.93±4.18 cells/sample (p < 0.05).

CONCLUSIONS

In this pilot cohort, antimicrobial peptide-based postbiotic therapy was associated with encouraging pregnancy outcomes and targeted pathogen clearance. The intervention selectively reduced high-burden detrimental taxa while maintaining microbiome architectural integrity, supporting precision microecological modulation as a promising adjuvant strategy for reproductive health.