I remember spending hours reading about embryo quality and implantation during my IVF cycles, but I barely thought about what happened to the embryos once they were frozen! It's strange how much we focus on getting good embryos and how little we actually know about what happens in the lab afterwards. Did your clinic explain their freezing and storage process at all, or did they just tell you the embryos were being frozen?
4 blastocysts is such a huge thing to go through IVF for, so I get why you’re questioning every step now! I honestly think asking the clinic how they freeze and monitor the embryos is worth doing, just so you know exactly what’s happening rather than sitting there worrying about it. Did they give you any information about vitrification when they froze them!