Embryos leftover from an IVF and ICSI cycle may be stored and used for subsequent cycles should a couple wish to have conceived again or at a later stage in life. The freezing of embryos is termed Cryopreservation and the process by which it is done is called Vitrification.
Vitrification is achieved by quickly plunging the embryos into freezing liquid Nitrogen. The speed with which this is done ensures that water in the embryos doesn’t crystallize into ice crystals. Embryos may be stored from between 10 – 55 years.
The advantage of being able to utilize frozen embryos is that a couple can put off another pregnancy for whatever reason, without being too limited by increasing maternal age. Additionally, it costs less to use embryos frozen from a previous cycle when compared with a whole new Assisted Reproductive Cycle. However, it is worthy to note that frozen and thawed embryos have a lower viability rate when compared with fresh embryos created from a current cycle.