Vitrification 

Vitrification is a modern method of rapid freezing (cryopreservation) that allows us to safely, gently and efficiently preserve eggs and embryos in our laboratories until you need them.

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What is vitrification?

Vitrification allows cells to be preserved in high quality and viable for future use.


To increase the success rates of IVF treatment, we strive to obtain a higher number of quality eggs with the subsequent transfer of one embryo. The remaining reproductive cells are then treated to maintain the same quality in the long term, depending on individual needs and the development of the treatment.

Due to the susceptibility of the eggs and embryos to damage, we use vitrification, the latest technology for rapid freezing.

Freezing eggs and embryos — vitrification step by step:

Eggs or embryos go through a precise sequence of processes, during which the cells are gradually prepared and protected by cryoprotective solutions. Each step has a set time limit.


  1. The sample with cryoprotectant is quickly cooled to a very low temperature (-196 °C) using liquid nitrogen. The rapid cooling process allows the formation of a glassy ice structure instead of a crystalline mould.
  2. The frozen sample is stored in cryogenic containers with liquid nitrogen. The containers we use at the Prague Fertility Centre laboratories are among the most modern specialised devices of their kind in the Czech Republic.
  3. Thawing takes place only a few hours before the material is used. It starts with a quick immersion of the sample in a special solution at body temperature. We then gradually and gently wash out the cryoprotectants to prevent damage to the cell.

Main benefits of vitrification: 

  • Minimises the risk of cell damage The treatment with cryoprotectant agents and subsequent rapid freezing to very low temperatures prevents formation of ice crystals that could potentially disrupt the cell structure.
  • Maintains eggs and embryos with the same quality as in the case of fresh cells Implantation success rates of the frozen embryos are higher (43% vitrified vs. 35% fresh embryos), with clinical pregnancies, it is even 13 % more (57% vitrified vs. 44% fresh embryos).

Vitrification is a relatively new laboratory method. It was developed in the 1980s as a safer and more effective alternative to what was the traditional slow cryopreservation method (which we still use to freeze less fragile sperm cells). In assisted reproduction, vitrification started to be employed in the 1990s. Since then, it has become a mainstay of modern IVF and the standard method for stable manipulation in the preservation of reproductive cells in personalised IVF treatment.

Vitrification of eggs and embryos is typically on our to-do’ list in our laboratory every day. This means your eggs and embryos are safe and sound with us and preserved until the time is right to use them. 

You can discuss your reproductive cell freezing options with our IVF Coordinators, who will guide you through the entire process whether you’re interested in preventative fertility preservation or fertility treatment.