IVF applying no medicines for ovarian hyperstimulation, although medication for ovulation suppression may still be utilized. During early blastocyst advancement, fluid starts to fill embryo. The embryo begins to expand similar to a balloon. To implant, the embryo have to escape in the shell surrounding it. This known as "hatching." https://privatebookmark.com/story18474230/5-simple-statements-about-assisted-reproductive-technology-explained