In some circumstances it may be recommended for sperm to be frozen. In such cases, the sperm sample is frozen in a medium (cryoprotectant) which protects against damage during the freezing process. The sperm can then be preserved for many years and used for fertility treatment in the future when the couple are ready for a child. Pregnancies have been reported from frozen-thawed sperm that have been stored for 15 years.
Sperm can be frozen and stored for a number of reasons:
- For men who have few sperm or perhaps are producing sperm that show evidence of deterioration over time.
- For couples undergoing fertility treatment where the man has difficulty producing a sample on the day of treatment and so banking sperm in advance can resolve this difficulty.
- For men who require surgical retrieval of sperm (MESA, PESA or TESE procedures).
- For men who are to undergo cancer treatment that may affect their future fertility.
- For men who are planning to have a vasectomy.
- For storing of donor sperm (sperm banking).
