Cryopreservation of unfertilized oocytes is a method recently introduced in the field of assisted reproduction and applied in cases such as:
· Women suffering from premature ovarian failure
· Women undergoing oncological treatment, and therefore being at high risk of fertilizing capacity loss
· Women wishing to preserve their fertility at a younger age and postpone starting a family
· Couples wishing to avoid freezing embryos for ethical or religious reasons
The first report of pregnancy achieved from frozen oocytes was by Chen in 1986. Since then, few children were born worldwide, because the process of cryopreserving unfertilized eggs by the slow-freezing method had poor success rates. The main reason was the difficulty in cryopreserving cells with high water content, such as oocytes.
Conversely, a recent modification of the vitrification method may be successfully used for cryopreservation of unfertilized eggs, according to the literature. The survival rate of oocytes after thawing exceeds 90%, the fertilization rate is about 70% and the pregnancy rate is higher than 40%. Cryopreservation of unfertilized oocytes is a promising method, that meets the needs of Greek women in modern living conditions; it seems the method has lot to offer in the field of assisted reproduction.