Why is it necessary to freeze and preserve the remaining high quality embryos after IVF transfer? Embryo cryopreservation is the process of freezing and preserving the remaining good quality embryos from one ovulation cycle at ultra-low temperature (-190°C) for later transfer after embryo thawing and recovery (e.g. if the current transfer fails or if you want to have a second child many years later). It helps to save money and not waste the quality follicles retrieved after one ovulation treatment. What are the risks of embryo freezing? Embryo cryopreservation and transfer after thawing and recovery is a mature technology, but due to the difference in embryo quality, there is a possibility of embryo recovery failure and no transferable embryos. Resuscitated embryo pregnancies are at risk of miscarriage, ectopic pregnancy, fetal/neonatal malformations, and other pregnancy and delivery complications, just like natural pregnancies, with no significant difference in the probability.