Cryopreservation in liquid nitrogen (-196oC) helps spermatozoa keep their activity for a long time enabling the use of sperm in various assisted reproduction techniques (insemination, IVF, ICSI). The tremendous developments in the field of assisted reproduction have helped a lot of men suffering from cancer or other diseases which could lead to infertility to have children of their own. A carefully cryopreserved sperm or testicular tissue sample remains vital for a long period of time (up to 20 years) before being used in an assisted reproduction technology. Patients who will decide to cryopreserve their sperm should abstain from any sexual activity for at least 2 – 5 days before giving a sample and they should have completed screening for HIV and Hepatitis B, C and VDRL at least 30 days prior to the day they will give the sample.
A sperm sample is collected by masturbation in a sterilised cup in our premises. Analysis of the sample and suitable preparation are then followed according to specific protocols and then placed in liquid nitrogen for cryopreservation. During the whole period of its cryopreservation, the sperm belongs to the patient who provided it, whereas our Unit is responsible for its careful and proper preservation. Most patients should provide at least two sperm samples between 48 – 72 hours. This provides a satisfactory number of spermatozoa for future use.
Advantages and risks:
The advantages of cryopreservation include:
- The possibility of a pregnancy in the future.
- The preservation of a presently healthy sperm sample for future use when it will probably be less satisfactory or even will lack spermatozoa.
- The use of the cryopreserved sample (for insemination or IVF) when a fresh sperm sample would not be available.
Cases in which sperm cryopreservation is beneficial for the male partner.
- Future surgery, X-ray therapy, chemotherapy or other treatments that may influence the fertilising capacity of the sperm.
- Absence of the male partner at the date allocated as the most preferable for IUI or IVF.
The risks of sperm cryopreservation include:
- The uncertainty of whether the cryopreserved sperm will lead to pregnancy once thawed. Pregnancy rates with the use of cryopreserved sperm are slightly lower than those using fresh sperm as several characteristics of the spermatozoa such as motility and vitality are influenced even though the embryo that will eventually result from cryopreserved sperm is usually normal.
- The possibility of a failure in the storing equipment.
Testicular tissue cryopreservation
In cases of azoospermia, testicular tissue biopsy is performed in order to verify the presence of spermatozoa or the possibility of a malignancy and then to retrieve any spermatozoa present. Before the biopsy, FSH and inhibin A levels are checked to evaluate the state of the vas deferens. If the levels are high, three tissue specimens are taken from each testicle which are then placed in special tubes and preserved in liquid nitrogen (-196oC) and remain there until used.