Implication of the Vaginal Microbiome in Female Infertility and Assisted Conception Outcomes

The rise in infertility rates has prompted research into the impact of vaginal microbiota on female fertility and the success of assisted reproductive technology (ART). Our study aimed to compare the vaginal microbiome between fertile and infertile women and explore its influence on ART outcomes. Vaginal secretion samples were collected from 194 infertile women and 100 healthy controls at Shanghai Changzheng Hospital. The V3-V4 region of the 16S rRNA gene was amplified using polymerase chain reaction (PCR). A machine learning model was applied to predict infertility based on genus-level abundance, and the PICRUSt algorithm was employed to predict metabolic pathways related to infertility and ART outcomes. The results showed that infertile women exhibited a significantly different vaginal microbial composition compared to healthy controls, along with increased microbial diversity. Notably, the abundance of Burkholderia, Pseudomonas, and Prevotella was significantly elevated in the vaginal microbiota of the infertility group, while that of Bifidobacterium and Lactobacillus was reduced. Among infertile women, those with recurrent implantation failure (RIF) showed even higher vaginal microbial diversity, with specific genera such as Mobiluncus, Peptoniphilus, Prevotella, and Varibaculum being more abundant. Eleven metabolic pathways were identified to be associated with both RIF and infertility, with Prevotella showing stronger correlations with these pathways. This study elucidates differences in vaginal microbiome between healthy and infertile women, providing novel insights into how vaginal microbiota may impact infertility and ART outcomes. Our findings underscore the importance of specific microbial taxa in women with RIF, suggesting potential avenues for targeted interventions to improve embryo transplantation success rates.