Cryopreservation is a technique that has been in practice for decades in various medical branches. Cryopreservation involves freezing of biological material at extreme temperatures, at which all biological activities of the cells stop entirely. Even the biochemical reactions that can lead to DNA degradation and cell death will be stopped. The temperature used is as low as -196° C / -321° F and the commonly used medium is liquid nitrogen.

Cryopreservation technique is used to freeze the eggs, sperms or embryos collected from the human body for later use or in other words the technique is used to preserve human fertility for several years till one desires.

These cryopreserved eggs, sperms or embryos are thawed and used in In-Vitro Fertilization (IVF).

These cryopreserved sperms can also be used in (Intrauterine Insemination (IUI) procedure.



Sperm Cryopreservation is a process of storing sperms in a frozen state for future use. This procedure is also used in Sperm Banking.

Preservation Procedure

  1. Collection - Semen samples should be produced by masterbation in specific semen collection rooms in the lab or hospital, so that the embryologists can prepare and freeze it as soon as possible.
    • No lubricant should be used as this can damage sperm.
    • All of the semen produced, should be collected as the first portion often contains the most sperm.
    • Any kind of ejaculation must be abstained for 2 - 3 days prior to the procedure to maximise the sperm count.
  2. Sample Preparation - The semen sample is collected in a sterile dish and is analyzed for volume, viscosity, sperm motility, sperm count and other factors.
  3. Freezing - Cryoprotectants are added to prevent any ice crystallisation that can occur during freezing. Cooling is done over a period of 2 - 4 hours. Then the specimen is placed into liquid nitrogen at -196°C.

One can opt to use the sperm at any time, even after several years. The frozen sample is thawed and then used for artificial insemination or egg fertilisation.

Vitrification is an amazing breakthrough for preserving sperms, eggs and embryos. It is an advanced technique, a potential alternative to slow freezing that leads to a glass-like formation. The word ‘Vitrification’ comes from the Latin word ‘Vitrum’ meaning glass. The process involves sudden cooling of the reproductive cells to -196°C so rapidly (within seconds) that the water molecules don’t get the time to form ice crystals, but instead immediately solidify into a glass-like structure thus avoiding freezing injuries to the sperms, eggs or embryos.


The key to the whole process is a smooth transfer of the natural fluid out of the sperms, eggs or embryos, while it is made sure that the antifreeze is slowly flowing in at the same time.

The sperms, eggs or embryos are exposed to a high concentration of cryoprotectants, which allows rapid dehydration of the reproductive cells.


The sperms, eggs or embryos are then loaded into tiny storage devices that will facilitate ultra-rapid cooling.


Then, the storage devices are cooled as fast as possible at around 1000OC per minute.


The high cooling rate combined with the use of high concentrations of cryoprotectants allow the contents of the storage device (that is sperm / oocyte / embryo and the fluid) to turn into a glass-like substance instead of ice.


Then they are stored in sealed casting that is kept in liquid nitrogen (-196°C).


Who is this for?  

Except for Sperm, Egg and Embryo Banking, vitrification is used for the following cases

  • Inappropriate hormonal profile
  • Risk of Ovarian Hyper Stimulation Syndrome (OHSS) has approximately 5-10% cases of ovarian hyperstimulation, i.e. excessive reaction of the ovaries to hormonal stimulation, occurs in women undergoing extracorporeal (occurring outside the body) fertilisation. In such situations, it is not advisable to transfer fresh embryos due to medical reasons. Therefore, all embryos are frozen and transferred after hyperstimulation has entirely subsided.
  • Doctors recommend frozen embryo transfer (FET) in cases, where there is Polyps, Hydrosalpinx or Hydrometra.
  • Absence of Spermatozoa
    If potential sperm is not available on the day of the oocyte retrieval, frozen sperm is used for fertilisation.

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