The blastocyst stage is the last embryonic stage before implantation and is assumed to be the best stage of embryo selection compared to embryo at cleavage stage. Even when using the most advanced culture media not every embryo will reach the blastocyst stage and transfer them at day 5 [1]. From the time-lapse literature as regards to embryo selection that is successful outcome from the transfer of a blastocyst depends partially on it reaching that stage but even more that how and when it reached. Simple watching the emerging fluid filled space in a morula depends on the underlying works of a number of ordered molecular interactions. Blastulation is a complex process, with the resulting blastocyst representing the successful derivation of divergent cell lineages, a culmination of an ordered sequence of processes which begin with a ''start signal '', compaction, in mammalian embryos. Sozen B et al. [2] reviewed this process, explaining, how it begins as junctional complexes form at apico lateral and lateral sites on blastomeres, that is followed by polarization within the outer cell mass.

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