[Does embryo morphology constitute a reliable criterion for embryo selection?]

Embryo selection based exclusively on embryo morphological criteria does not allow currently to obtain satisfactory implantation rates. So, new time-lapse systems have been proposed to improve the rates of in vitro fertilization success. However, the profit/investment ratio of time-lapse systems and the interest of embryo morphokinetics evaluation remain clearly to be established by clinical, robust, prospective, and randomized trials. Consequently, morphological and morphokinetic approaches showed their limitations and justify the development of new non-invasive "omics" approaches. These approaches are very promising and have for main aim to identify new non-invasive biomarkers, in oocyte microenvironment and/or in embryo culture medium, predictive of oocyte and/or embryo quality as well as pregnancy rates. These approaches thus open the way to develop new diagnostic and/or prognostic tests for embryo viability based on the expression and/or the quantification of biomarkers of interest in assisted reproductive technology.