PGT-A tested embryos for embryo transfer (ET) or frozen embryo transfer (FET), a small hatching blastocyst seems to be a ...

Blastocysts are normally protected from external influences by a coat, the zona pellucida; before the embryo implants in the uterus, the young embryo "hatches" from this protective cover.

Early embryonic cell polarity and lineage differentiation, which are vital to implantation, and continued embryonic growth climax with the onset of blastocyst formation. These processes are ...