Embryo cryopreservation is the process of freezing embryos (fertilized eggs) for their subsequent use. This method is often used in reproductive medicine. That's how it happens.:

  1.  Embryo preparation: Embryos are created by fertilizing eggs with sperm in the laboratory using the in vitro procedure (IVF).
  2.  Embryo freezing: Usually, before cryopreservation, the embryos are cultured for several days to ensure their quality. They can then be frozen using special substances to keep them stable.
  3.  Storage: Frozen embryos can be stored in special containers at very low temperatures (usually about -196 degrees Celsius) in special containers filled with liquid nitrogen.
  4.  Defrosting and Transfer: When the time comes, the embryos can be thawed and transferred to the woman's uterus for possible implantation and pregnancy.

This process allows people to freeze and preserve their embryos for a long time, which gives them flexibility in family planning and pregnancy.