When a woman desires to vitrify her oocytes, firstly she has to undergo multiple ovulation induction, in order to maturate a satisfying number of oocytes. This stage of the therapy requires about 10-12 days since the first day of the menstrual cycle. Then, the doctor collects the oocytes after the oocyte pick up procedure. The oocytes can be vitrified only after their suitable elaboration in the lab and only if they are assessed as mature. The oocytes are cryopreserved with the method of vitrification, which ensures the best results. The oocytes that can be vitrified have to be at the stage of the metaphase II, of the second meiotic division of the cell cycle.
The oocytes are then vitrified in very low temperatures avoiding the formation of crystals in the cytoplasm. In order for that to happen, a high concentration of cryoprotectant substances are used. This step is necessary as it protects the cytoplasmatic membrane of the oocytes, so that the cell will remain alive. After this preparation, the oocytes are immediately immersed in liquid nitrogen and as a result they get vitrified. The vitrified oocytes are maintained in liquid nitrogen storage tanks.
Later, when the couple decides to have a child, the oocytes are thawed with a 90% percent survival rate, and then in vitro fertilised with the partner’s or donor’s sperm.