The cryopreservation of sperms is performed with the use of cryopresrvatives, which aim to protect the various cell structures of the sperm from the drastic change in temperature.
The cryoprserved samples are kept in liquid nitrogen at 196C and they can be maintained indefinitely in this temperature. The sample is placed in ampoules carrying the name, the specific code and the respective freezing date.
The sample is placed in a specific position in the nitrogen containers while the unique ID of each sample is maintained in a file in the laboratory. The file is accessible only to the embryologist. During the thawing phase, the sample experiences a partial loss of spermatozoa motility, as high as 40%. Samples with a small number of spermatozoa, or limited motility are usually unsuitable for cryopreservation, since the sample will be unsuitable for fertilization after thawing.
The freezing of sperms is proposed in the following cases:
Subject to the provisions of the law, the cryopreserved sample is kept for a period of 5 years in the case it was provided by the male partner himself and for a period of 10 years, if it was derived from a third party donor.