Effects of vaginal microbiota on <i>in vitro</i> fertilization outcomes in women with different infertility causes

Many studies suggest that vaginal microbiota (VMB) may affect <i>in vitro</i> fertilization-embryo transfer (IVF-ET) outcomes. Assessing VMB before embryo transfer can optimize timing for better assisted reproductive technology (ART) results. This study examined VMB distribution in infertile women undergoing ART using 16S rRNA sequencing. Results revealed that VMB structure impacted ART outcomes in women with polycystic ovary syndrome (PCOS) and tubal factor infertility (TFI) before embryo transfer ([less than or equal to] 24 hours). <i>Lactobacillus iners</i> and <i>Pseudomonas</i> spp. were identified as adverse factors for post-ET pregnancy. The study also showed differences in pre-ET VMB between normal women and women with PCOS and TFI during the ovulatory window. These findings highlight the importance of considering VMB composition to optimize embryo transfer timing and personalize ART treatment based on infertility type, improving the chances of success.