Role of miRNAs in preimplantation embryo development and their potential as embryo selection biomarkers

MicroRNAs (miRNAs) play different roles in oocyte fertilisation, degradation of maternal transcripts, embryo development, and implantation. During in vitro fertilisation (IVF), different miRNAs are released from embryos into the spent culture media (SCM) that can potentially reflect the status of the embryo. This study is the assessment of miRNAs, which secreted in SCM during the IVF cycles can be used as noninvasive biomarkers to predict an embryo's ability to form a blastocyst, implant, and give live birth. Systematic literature search was conducted to review all recent studies about miRNAs as potential non-invasive biomarkers for selecting the best embryos in the assisted reproductive technology (ART) cycle. Studies have shown that levels of some miRNAs in the SCM have an association with the implantation potential and pregnancy outcome of the embryo. Embryo-secreted miRNAs can be used as potential non-invasive biomarkers for selecting the best embryos in the ART cycle. Unfortunately, few human studies evaluated the association between ART outcomes and miRNAs in SCM. This review can pave the way for further miRNAs transcriptomic studies on human embryo culture media and introducing a specific miRNA profile as a multivariable prediction model for embryo selection in IVF cycles.