MicroRNAs as Biomarkers and Therapeutic Targets in Female Infertility.

The study of microRNAs (miRNAs) has emerged in recent decades as a key approach to understanding the pathophysiology of many diseases, exploring their potential role as biomarkers, and testing their use as future treatments. Not only have neurological, cardiovascular diseases, or cancer benefited from this research but also infertility. Female infertility, as a disease, involves alterations at multiple levels, such as ovarian and uterine alterations. This review compiles the latest studies published in humans that link female disorders that affect fertility with altered miRNA profiles. Studies on ovarian alterations, including diminished ovarian reserve (DOR), poor ovarian response to stimulation (POR), premature ovarian insufficiency (POI), and polycystic ovary syndrome (PCOS), are summarized and classified based on the expression and type of sample analyzed. Regarding uterine disorders, this review highlights upregulated and downregulated miRNAs primarily identified as biomarkers for endometriosis, adenomyosis, decreased endometrial receptivity, and implantation failure. However, despite the large number of studies in this field, the same limitations that reduce reproducibility are often observed. Therefore, at the end of this review, the main limitations of this type of study are described, as well as specific precautions or safety measures that should be considered when handling miRNAs.