During a fresh IVF cycle there may be some surplus embryos created.
Cryopreservation is the freezing and thawing of these embryos for use in future IVF cycles.
The major advantages to using cryopreserved embryos in future IVF cycles, is that ovulation induction is avoided which also dramatically reduces medication cost. Success rates are variable depending on patient characteristics, embryo quality and clinical history. In general, however,success rates are lower than fresh cycles.
A happy note to couples that have the opportunity to use frozen embryos is the children are healthy and normal. Many studies have evaluated the children born from frozen embryos (“frosties”). The result has uniformly been positive with no increase in birth defects or development abnormalities.
In summary, embryo cryopreservation adds an important dimension to assisted reproduction. It extends the possibility for pregnancy when fresh cycles fail or when couples want additional children after a successful embryo transfer. Cryopreservation helps avoid many ethical dilemmas by eliminating the need to dispose of embryos for couples unwilling to donate them to other couples or to scientific investigation. It also offers an alternative to couples that might transfer too many embryos and risk a multiple gestation pregnancy.
In some cases it is advisable to freeze sperm. Some men have very few sperm or perhaps are producing sperm that show evidence of deterioration over time. Other men have difficulty producing a sample on the day of treatment and so banking some sperm in advance can reduce this difficulty.
Sperm can also be frozen for men who are about to undergo surgery, chemotherapy or radiotherapy that may impair their future fertility.
Sperm is frozen in a medium (cryoprotectant) that protects them from damage during the freezing process. Consent is required to freeze sperm and it can be frozen in excess of 20 years. There is no evidence that sperm deteriorates over time in storage