Sperm freezing step by step: how we preserve male fertility
Semen freezing is a technique widely used in assisted reproduction laboratories, as it allows us to preserve male fertility. Thanks to this technique, we are able to cryopreserve the sperm contained in semen and store it for future use in assisted reproduction techniques.
Sperm cryopreservation is a process in which sperm are frozen at very low temperatures (between -80ºC and -196ºC), so that their vital functions are suspended and can be recovered after thawing.
How is male fertility preserved through semen freezing? You probably have questions about this, so we have prepared this article to explain step by step what this technique involves.
Why is semen frozen?
The first thing you should know about semen freezing is that the main objective of sperm cryopreservation is to preserve male fertility, since, as you can imagine, this is also important in assisted reproduction, and is sometimes compromised for various reasons. For example:
– Diseases or medical treatments that can affect sperm production, such as testicular tumours or cancer treatments involving chemotherapy and/or radiotherapy.
– Poor semen quality, which can worsen over time.
– Vasectomy, in which case one or more semen samples can be frozen before the procedure to avoid a surgical process (vasovasostomy or testicular biopsy) if offspring are desired in the future.
Apart from these situations, it is also common to freeze semen when the couple is undergoing assisted reproduction and there is no certainty that the sample will be available on the day of insemination. This can happen, for example, if the man has difficulty collecting the sample or travels frequently.
What is the procedure for freezing semen?
Before freezing a semen sample, it is very important to obtain a good assessment through a semen analysis. To do this, the doctor and biologist will take into account the most important parameters of this fertility diagnostic test (sperm count, morphology, motility and ejaculate volume) in order to advise the man or couple on the number of samples to cryopreserve and the best way to do so.
Since cryopreserved sperm samples are stored in sperm banks along with others, for safety and legal reasons it is essential that the man provides a recent serology test before freezing.
How is semen frozen and stored?
The semen sample to be frozen must be collected by masturbation in a sterile container and delivered to the laboratory as soon as possible, so it is advisable to obtain it at the facilities provided for this purpose at the reproduction clinic.
Before leaving the semen sample, a period of sexual abstinence of between three and five days is recommended. However, in urgent cases, sperm can be frozen without this period of abstinence.
To freeze semen, the sample is subjected to a gradual and controlled decrease in temperature until it is finally immersed in liquid nitrogen. The cellular damage caused by this extreme cooling is prevented by using cryoprotectants, and although some sperm will be damaged during the freezing-thawing process, the survivors will maintain the same quality as those that have not been frozen.
The semen samples to be frozen are distributed in small tubes or straws of approximately 0.5 millilitres, perfectly sealed and labelled, which are stored in semen banks. In certain cases, due to the special value of the semen (from cancer patients, HIV washes, testicular biopsies, etc.), it will be cryopreserved in small pills that can be thawed one by one, thus increasing the chances of achieving offspring through assisted reproduction techniques.
How long can semen be kept frozen?
So far, no evidence has been found that time affects the quality of cryopreserved sperm. Therefore, samples can be frozen for as long as necessary. In fact, there are known cases of pregnancies achieved with sperm that had been frozen for more than twenty years…
As you can see, freezing semen is an assisted reproduction technique that helps us preserve fertility. If you find yourself in one of the situations described above, or if you have questions about this process and would like to consult us, at URE Centro Gutenberg we are here to listen and help you resolve any issues.