ABSTRACT
CRYOPRESERVATION OF HUMAN GAMETES AND EMBRYOS, ITS APPLICATION, AND THE IMPORTANCE OF STABILITY DURING STORAGE Around 8%–12% of couples of reproductive age experience diculties conceiving, and may seek treatment using assisted reproductive technology (ART). Since the birth of the rst in vitro fertilization (IVF) child Louise Brown in 1978, a number of new techniques have been developed. Hormone-stimulation protocols were established to obtain a number of oocytes per cycle and ovarian pick-up. Intracellular sperm injection was implemented to treatment couples diagnosed with severe male infertility. All these techniques have contributed to the success of ART, and have led toward a time in which it is now standard to obtain more than one (or two) embryos per stimulation cycle. erefore, cryopreservation of embryos has become an essential part of IVF. Nowadays, many aspects even favor the “freeze-all” strategy, in which embryos are cryopreserved aer ovarian stimulation and IVF, and then transferred in a subsequent cryo-cycle, avoiding articial hormonal levels.1 Embryo and oocyte freezing is applied for fertility preservation in cancer patients, and also in women planning delayed child bearing. Due to this technological progression, the storage time of cryopreserved embryos has arisen as an important issue. According to diering legislation in dierent countries, storage of cryopreserved gametes and embryos may be utilized for several years, or even decades.
