Gametes can undergo cryopreservation for long-term storage. The samples are safely kept in specialized Liquid Nitrogen tanks, at temperatures of -196°C. It is essential for patients who will have their gametes stored, to undergo blood testing for Hepatitis B (HBsAg), Hepatitis C (HCV), HIV 1&2, and VDRL (syphilis), prior to the cryopreservation of their samples.
It is a procedure that aims to preserve sperm cells. The sample is mixed with a cryoprotectant to protect the sperm cells from the low temperature and stored in cryovials for future use.
In what cases is it recommended?
The main reasons for cryopreserving semen samples are the following:
- After surgical sperm retrieval (PESA, MESA, TESA, TESE) in azoospermic men, in order to avoid repeating the procedure in the future
- Patients with low sperm count that risk of becoming azoospermic or with compromised sperm quality with signs of decline
- For patients who, for psychological reasons, may not be able to produce a fresh sample on the day of the egg collection
- For patients whose fertility may become compromised following cancer treatment
- For patients with other medical issues such as spinal cord injuries, exposure to toxic waste and/or chemicals, radiation and lead poisoning, testicular injuries (for example in athletes), and any other conditions that may lead to partial or total azoospermia
- Prior to male sterilization via vasectomy
- In cases where the male partner may be unavailable to produce a semen sample on the day of egg collection/oocyte donation, due to social/professional reasons
Oocytes are cryopreserved using “vitrification”, a relatively new and rapid technique that minimizes crystal formation in the intracellular and extra-cellular space of the oocyte hence potential damage during the freezing and thawing process is minimized. The introduction of this technique has revolutionized oocyte cryopreservation and has become a viable option for many women, who for different reasons wish to have their oocytes stored for future use.
What are the main reasons to opt for oocyte cryopreservation?
- For social reasons, i.e. for women who wish to delay motherhood and do not have a male partner. The demanding modern lifestyle, along with financial reasons and increased professional responsibilities have resulted in women wishing to delay motherhood. Since fertility becomes compromised particularly after the age of 35, more and more women choose to have their oocytes cryopreserved at a younger age
- For female patients whose fertility may become compromised following cancer treatment
- For patients with other medical issues such as spinal cord injuries, exposure to toxic waste and/or chemicals, and any other conditions that may lead to compromised fertility or to the removal of the ovaries
- For patients who respond poorly to stimulation hormones, for the purpose of oocyte accumulation, to be used in a future treatment cycle
- Stimulation with hormonal medication may result in the retrieval of multiple oocytes. Surplus oocytes can be cryopreserved for use in the future when embryo cryopreservation is not feasible (for religious reasons or due to the unavailability of sufficient spermatozoa)
Does oocyte cryopreservation affect the ability to conceive naturally in the future?
This is a common concern, but you will be relieved to know, that the answer is “no”.
During every cycle, a certain number of follicles is recruited, but naturally, only one will grow and the oocyte will eventually be ovulated. The remaining follicles will naturally wither and fade away. When stimulation hormones are being used for the purpose of oocyte cryopreservation, all the recruited follicles are stimulated to continue their growth, which will allow the collection of a greater number of oocytes to be eventually cryopreserved. As a result, this will have no effect on the woman’s future fertility, nor will it speed up menopause.