Crypreservation of oocytes is recently being considered to be a valid choice in infertility treatments.Low survival and fertilization rates due to inefficient slow freeze protocols have been the outcome ofmany previous studies done in the field. However, introduction of the Vitrification technique and itsapplication in reproductive medicine and to some extent new improved slow freeze protocols haveshown that oocytes can be cryopreserved with successful outcome.In this project the survival rate of oocytes after Vitrification with MediCult Vitrification andWarming Media has been studied. Also, a comparison of the carriers Cryoloop (an open system) andCryopette (a closed system) has been performed.A total of 43 oocytes were vitrified and warmed according to MediCult's protocol, of which 21oocytes with Cryoloop and 22 with Cryopette. The cells were post-thaw incubated in a physiologicalenvironment for 24h. During that time the morphology and viability were observed and noted after 2h,over night and after 24h.

Ovarian stimulation in assisted reproduction often leads to the production of a high number of oocytes. After fertilization of these oocytes, the resulting embryos can be cryopreserved for later use. Vitrification is a recently introduced method for cryostoring embryos, showing high survival rates for both cleavage stage embryos and blastocysts. Characteristic of Vitrification are high concentrations of cryoprotectants and ultra fast freezing which makes the material glassily. A major concern with Vitrification has been the direct contact of the cryo-solutions with liquid nitrogen.