Unconventional embryo selection strategies: a look into the future

The assessment of an unequivocal method able to identify the embryo with the higher possibility to implant, leading to a single live birth, is crucial for the success of an infertility treatment. Standard morphology evaluation, morphokinetic analysis and preimplantation genetic screening are the more employed embryo selection strategies in reproductive medicine centers. However, the results and the applicability of these methodologies are still controversial. Therefore, there is the need to find additional technologies to clinically select developing embryos. The challenge is to set-up a predictive, not invasive, reproducible, objective and effective method able to select the best embryo. In this review, we present several unconventional methodologies of embryo evaluation, analyzing their possible future application in human reproduction.