Slow freezing of human mature oocytes:: High survival and fertilization rates after thawing Oocytes obtained by recombinant FSH stimulation

Oocyte criopreservation it has been proposed as a method to assure the preservation of a female genetic material and to use it for different pourpouse like: postpone motherhood and menopause, or to maintain an oocyte reserve in patients with some malignant disease before the treatment. Also this technique may resolve some ethic issues regarding the embryo criopreservation. The delay to the application of the oocyte criopreservation to the clinical use was due to technical problems related to the cryobiology of the oocyte cell. Recent advances in the knowledge of new crioprotectants agents, modification of their concentration and time of exposure to the oocyte to them, encourages to have better results to use this technique in humans. Our study shows that human oocytes at MII stage, obtained by r-FSH stimulation protocols, and cryopreserved by slow freezing have a high survival and fertilization rates after thawing. Probably this is a good option to use in the ART routine nowadays.