Cryopreservation - storing a sperm sample in liquid nitrogen
The cryopreservation of sperm samples is used in the following cases:
a) In men who have had difficulty collecting sperm in the past
It has often been observed that on the day on which the sperm sample needs to be collected for insemination or in vitro fertilisation, the man is unable to collect a sperm sample for psychological reasons. If this is known from prior experience, a sperm sample is provided at any time and kept frozen. The term ‘frozen’ means deep freeze in liquid nitrogen, at a temperature of -196 °C. This procedure is carried out in order for the man to feel that there is an available sample, a fact that usually helps him produce a sperm sample on the day it is needed. If this is not possible, the frozen sample is used.
b) In men who, due to work obligations, are often absent from their place of residence
This may result in the husband being absent on the day his sperm is required either for insemination or for IVF. In such cases, with the consent of his wife, a sperm sample is frozen in order to avoid concern on whether he will be able to be present on the day in question.
c) In men with a serious disease
In this case, cryopreservation is applied if the man is suffering from a serious disease, e.g., malignancies, which are the most common case, that require chemotherapy or radiation treatment. It is well-known that, in some cases, and depending on the medication administered, permanent damage may be caused to the testicles.
So, before undergoing such treatments and operations, the men concerned provide sperm samples to be cryopreserved, so that the husband can complete his treatment and, if his sperm cannot be used, his wife’s ova can be fertilised with the cryopreserved sample and pregnancy can be achieved with the couple’s own genetic material.
d) In the case of men who work with very toxic materials or in hazardous environments, where they may lose their fertility or be seriously or fatally injured, e.g., male soldiers stationed in war zones.
Based on national law it is possible for a special notarised consent form to be prepared for the fertilisation of the wife with the sperm stored, in the event of her husband’s death.
For this to happen the procedure must have been concluded prior to the death provided legal provisions have also been observed.
In cryopreservation, the man provides one, two or three sperm samples which are mixed with certain other cryoprotectant substances to shield the spermatozoa from any potentially negative effects of deep freezing.
Subsequently, the sperm is divided into small vials with a tag bearing the name, data and date affixed and they are cryopreserved in a specific area of containers filled with liquid nitrogen, so that they may be retrieved when a sample is needed.
Survival of biological samples in deep freeze is indefinite - in theory.