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    Donor sperm

    The first successful frozen sperm pregnancy was reported in 1953 and ever since there has been an exponential demand for donor sperm. Learn more about what donor sperm is and about the freezing process of sperm.

    What is donor sperm?

    Donor sperm is sperm/semen donated by a man to a fertility clinic or to a sperm bank, to be used in the fertility treatment of a woman hoping to get pregnant.


    Close up of Cryos donor sperm cells for fertility treatment

    Preparation of the donor sperm

    Before a donation can take place, the sperm is tested to make sure that the quality is good enough for a sperm donation. The tests provide the possibility to look at the sperm count, which is the concentration of sperm cells pr. ml and the concentration of motile sperm pr. ml (also called motility or MOT). It is the motility that determines the quality of the sperm. A normal sperm count ranges from 15 to more than 200 million sperm cells per ml.

    The donor sperm is then prepared for various different artificial insemination methods, such as:

    The different artificial insemination methods require different preparation methods. The sperm is either frozen “raw”, containing all the natural fluids that are present in a normal ejaculation or the sperm is “washed”, meaning that the natural ejaculate fluids are removed. The purpose of washing the sperm is in order to separate the abnormal sperm cells and as a result, getting a high concentration of motile sperm cells. This is necessary for some treatments, but not all.

    Once the quality has been confirmed and the sperm is prepared for treatment, the donor sperm is concentrated into small batches and then put into straws to be frozen. 

    Frozen donor sperm

    When the donor sperm is frozen, specialized cryoprotectant (“anti-freeze”) agents are used to help facilitate the freezing process, and in order to prevent crystallized water from damaging the sperm cells. The sperm is gradually cooled using liquid nitrogen vapour and is then stored in a nitrogen tank at -196 degrees Celsius.

    The freezing of donor sperm is also known as, cryopreservation. At these extremely low temperatures, there is no biological activity and therefore no microbes or bacteria can attack the sperm. The sperm does not degrade, or age and cryopreservation is therefore considered to have no time limit.

    The primary concern with cryopreservation is that not all sperm survive the freezing and thawing process. However, because only sperm with a high concentration of sperm cells are approved for donation and moreover, because the sperm quality (MOT) is determined after the freezing and thawing process, the chance of having enough healthy sperm for fertility treatments is very high.

    Essentially, the capability of the surviving sperm cells to fertilize an embryo is not jeopardized during the freezing or thawing process.

    At Cryos we have more than 30 years of experience with cryopreservation. Our processes are highly standardized due to our computer-assisted sperm analysis, which enables us to make a precise quantitative assessment of the donor sperm quality.

    We continue to improve as technology advances, and we strive to always keep updated with the latest scientific trends.