Freezing and long-term storage of sperm

A common question about freezing sperm is, how long can sperm be held in the frozen state yet still be thawed and then used to achieve a viable pregnancy and healthy Canadian Health Care Store Online birth? At the time of writing, the longest duration between sperm banking and conception is 21 years as evidenced by a case report of a young man who stored sperm at age 17 prior to treatment for testicular cancer and then, after being found to be azoospermic,1 successfully used the samples to achieve a conception with his partner at the age of 38. It is only a matter of time before this record is surpassed and from a theoretical standpoint there is no reason why sperm may not be kept frozen for much longer and still remain functional.

In the cattle breeding industry, for example, it is known anecdotally that sperm from some bulls has been successfully used to sire calves over 40 years after it was first frozen! However, such data remains unpublished and there are theoretical concerns as to the integrity of the nuclear DNA in samples that have been held in storage for a long period of time. This is particularly relevant to fertility preservation of men prior to medical treatments, because there is some evidence to suggest that the process of freezing and thawing itself can lead to DNA damage in sperm, at least in infertile men.

Conception following medical treatments

Although the effects of chemotherapy and radiotherapy on the male reproductive system are well documented, the precise effects on any one individual remain difficult to predict.

For males who are already producing sperm at the time of diagnosis and treatment (i.e. they have passed through puberty) there is a growing body of evidence to suggest that, for some treatments at least, there can be a good chance of natural fertility returning in the months or years following the cessation of treatment. For example, in an examination of 1115 post-treatment semen analyses in 314 patients who had received gonadotoxic therapy over a 26-year period, Bahadur et al. found that the type of cancer (or disease) and the initial pre-treatment sperm concentration were the most significant factors governing post-treatment semen quality and the recovery of spermatogenesis.

For example, patients with lymphoma and leukaemia had the highest incidence of post-treatment azoospermia and oligozo-ospermia.2 However, while men with testicular cancer had the lowest pre-treatment sperm concentrations, they also had the lowest incidence of azoospermia after treatment. This confirms an earlier observation by Lampe et al. who in a follow-up study of 178 men after chemotherapy treatment for testicular germ cell cancer found that 80 per cent of men had recovered some sperm production after five years since chemotherapy with 60 per cent reaching normal levels. Across all disease states Bahadur et al. concluded that only 37 per cent of patients had permanent post-treatment azoospermia, which goes some way to explain why relatively few males return to use their sperm-banked samples in future years (see below) – that is, because the majority are able to conceive quite naturally with no need for medical assistance.