Female reproductive microbiome in fertility care

The microbiome has emerged as a critical determinant of female reproductive health and fertility outcomes. Although conventional infertility evaluations, encompassing medical history, ovulation assessment, uterine and tubal evaluation, genetic screening, hormonal profiling, and reproductive tract imaging, provide essential diagnostic information, a substantial proportion of infertility cases remain unexplained, prompting increased attention to microbial factors. This review provides a comprehensive, critical evaluation of the methods for assessing the female reproductive microbiome, spanning traditional culture-based microbiology to contemporary molecular approaches. We systematically discuss the diagnostic performance, clinical utility, and established techniques, including microscopic examination, Nugent scoring, and Amsel criteria, alongside modern molecular methods such as quantitative PCR panels, 16S rRNA gene sequencing, shotgun metagenomics, and other multiomics. Critically, we evaluate the current microbiome testing platforms in clinical validity and utility. We identify significant gaps between research-grade methodologies and clinically actionable diagnostics, including a lack of standardized protocols, inconsistent reporting of absolute bacterial loads vs. relative abundances, and limited validation against reproductive outcomes. We propose evidence-based criteria for selecting appropriate diagnostic approaches on the basis of clinical context and discuss emerging technologies, including multiomics integration for implementing microbiome assessment in fertility care.