Changes of the vaginal microenvironment in patients with subinvolution of uterus

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Background Vaginal microecology is normally in a dynamic balance. Vaginal delivery can disrupt this equilibrium, yet limited studies have investigated the correlation between the occurrence of subinvolution of uterus and alterations in the vaginal microbiota.Methods Vaginal secretions were collected 42 days postpartum from 30 patients with subinvolution of uterus (Group A) and 30 normal puerperae (Group B). Differences in the microbial composition between the two groups were evaluated via 16S rRNA gene sequencing. Intergroup taxonomic profiles and diversity variations were rigorously assessed.Results The alpha diversity revealed no significant differences between the two groups based on Chao1 and Observed Species indices, but showed significant differences in the Shannon and Simpson indices. The beta diversity analysis suggested significant compositional differences between the two groups. Group A exhibited a marked reduction in the relative abundance of Lactobacillus spp. Conversely, conditionally pathogenic bacteria, including Porphyromonas spp., were significantly enriched in Group A. Functional pathway prediction demonstrated a significant enrichment of bacterial toxin synthesis and lysine biosynthesis pathways in Group A. Furthermore, phenotypic analysis revealed significantly elevated proportions of Gram-negative and facultative anaerobes in the subinvolution group.Conclusion Subinvolution of uterus is closely associated with vaginal microecological imbalance, which may be related to the weakening of mucosal barrier function due to the reduction of Lactobacillus spp., chronic inflammation caused by the enrichment of conditionally pathogenic bacteria, and impaired uterine repair mediated by the disturbance of metabolic pathways. This finding is expected to provide new ideas for the prevention and treatment of subinvolution of uterus.