Sperm Freezing: Who Needs Fertility Preservation?
Before cancer treatment, before starting hormone therapy, before testicular surgery. When sperm freezing comes into consideration, how the process works, how long samples can be stored and what the chances of pregnancy are.
Fertility preservation is the topic in men's health most often discussed after it is too late. Yet sperm freezing usually requires only a few days of planning and can prevent an irreversible loss. The critical point is timing: after certain treatments have begun, sperm production may not return, and at that stage no option remains.
What is sperm freezing (cryopreservation)?
Sperm freezing is the storage of sperm from a semen sample, prepared with special protective solutions and kept at very low temperature in liquid nitrogen. At this temperature cellular activity effectively stops; when needed, the sample is thawed and used in assisted reproductive treatment. The method is not new and has been in use for many years.
Who is it recommended for?
- Before cancer treatment: the highest-priority group. Chemotherapy and radiotherapy can affect the cells that produce sperm; this effect may be temporary but may also be permanent. Taking a sample before treatment begins prevents a loss that cannot be made good afterwards. Testicular tumour, lymphoma and leukaemia are the diagnoses most often encountered here.
- Before starting testosterone or hormone therapy: externally administered testosterone suppresses sperm production, and counts can fall markedly depending on the duration of use. In most men recovery follows within months of stopping, but the timescale cannot be predicted.
- Before testicular or reproductive tract surgery: particularly for procedures involving both sides.
- In men whose semen values are deteriorating rapidly: where consecutive tests show a marked decline, storing while it is still possible is a sensible insurance.
- Tissue obtained during surgery for azoospermia: freezing sperm found at micro-TESE can reduce the need for a further operation in subsequent attempts.
- As a safeguard during IVF: a sample stored in advance protects the process if a sample cannot be produced on the day of transfer.
- Occupational or environmental exposure, long-term medication and similar risk situations.
How does the process work?
The steps are straightforward: current values are measured with a semen analysis and screening for infectious disease (HIV, hepatitis B and C, syphilis) is carried out. The sample is produced at the clinic, preferably after 2–5 days of abstinence. In the laboratory it is assessed, prepared with a protective solution, labelled and frozen. If the sperm count is low, more than one sample may be requested; this increases the number of doses available later. The whole process can be completed within a few days — decisive flexibility for patients due to start urgent cancer treatment.
How long can samples be stored?
Under appropriate conditions duration is not the limiting factor; pregnancies have been achieved with samples stored for many years. Storage periods and renewal requirements depend on legal regulation and the practice of the centre, which is why it is important to read the consent form and storage agreement from the outset and to note the annual renewal schedule.
What are the chances of pregnancy with frozen sperm?
Some sperm lose viability during thawing; this is expected and is taken into account when the sample is prepared. Depending on count and motility, thawed sperm is used in insemination or IVF; where the count is very low, intracytoplasmic sperm injection (ICSI) allows even a single sperm to be injected into an egg. This is why freezing even the small number of sperm found during surgery for azoospermia is worthwhile.
Success does not depend on the sperm alone: the woman's age and ovarian reserve, the method used and the experience of the centre are decisive. No increase in the risk of congenital anomalies has been reported in children born using frozen sperm.
When is it too late?
The critical threshold is that gonadotoxic treatment has already started. In a sample taken after the first cycle of chemotherapy the risk of sperm DNA damage is higher, and in some patients no sperm is found at all. Likewise, a sample may not be obtainable from a man who has been taking external testosterone for a long period. For this reason every man due to undergo oncological treatment should be told about fertility preservation before treatment begins. He may not be thinking about children at that moment; the decision can change years later, and at that point a stored sample changes the picture entirely.
Assoc. Prof. Zülfü Sertkaya practises in the field of urology and andrology in Istanbul; fertility preservation and planning in male infertility are carried out individually and with full confidentiality.