Analysis of the impact of changes in vaginal Flora during pregnancy on the risk of premature birth based on 16 s rDNA high-throughput sequencing.

OBJECTIVE

To investigate the impact of changes in the vaginal microbiota during pregnancy on the risk of preterm birth by analyzing the microbial composition and diversity in term and preterm pregnancies using 16S rDNA high-throughput sequencing.

METHODS

Vaginal microbiota samples from term (n = 101) and preterm (n = 16) pregnancies were obtained from the EMBL-EBI database (PRJNA393472) and analyzed using Illumina sequencing targeting the V3 + V4 regions of the 16S rDNA gene. Alpha and beta diversity indices were calculated, and the taxonomic composition was evaluated. LEfSe analysis identified microbial biomarkers with significant differences between groups, and functional analysis was performed using KEGG pathways and enzyme pathway analysis to explore metabolic characteristics.

RESULTS

Term pregnancies exhibited significantly higher microbial diversity, with increased abundance of Lactobacillus species associated with a stable vaginal environment, whereas preterm pregnancies showed lower diversity and increased abundance of Gardnerella, Megasphaera, and Corynebacterium, indicative of microbial dysbiosis. Functional pathway analysis revealed higher abundances of pathways associated with lipid and amino acid metabolism in the preterm group, suggesting an inflammatory environment potentially conducive to preterm labor. Correlation analysis indicated that specific genera were associated with maternal age, gestational age at sampling, and delivery timing.

CONCLUSION

Findings indicate a stable, diverse vaginal microbiota dominated by Lactobacillus is associated with term pregnancies, a shift towards dysbiosis characterized by Gardnerella and other genera may increase the risk of preterm birth. These insights highlight the potential for microbiome-based interventions to restore microbial balance as a strategy to mitigate preterm birth risk.