Morphological Evaluation of Cleavage-Stage Embryos and Blastocysts

Over the last two decades, methodologies for assessing embryo implantation potential have emerged, including time-lapse imaging systems, various “-omics” techniques (genomics, metabolomics, etc.), and artificial intelligence. However, all the aforementioned methods are flawed or controversial in varying degrees [1–3]. Thus, conventional morphological indicators of embryos are still used as the main rating parameters or criteria.