Vitrification of human oocyte using cryoloop

The cryopreservation of human oocyte would make a significant contribution toinfertility treatment, such as using it for oocyte donation and for patients a bout to lose ovarianfunction due to surgery or chemotherapy. despite of using standard freezing straws and cryovials oreven open pulled straws, only a few successful pregnancies have been arisen from cryopreservedhuman oocytes. this situation has been primarily attributed to poor survival, fertilization anddevelopment of cryopreserved oocytes.objective: the aim of this study was to evaluate the novel cryoloop vitrification method forcryopreservation of human oocytes.materials and methods: nine infertile couples participated in this study. in all women properregulation and desensitization was done using gnrh agonist during luteal phase. mature oocytesallocated into two groups randomly. in group i, 34 oocytes were vitrified in conventional straws,while in group ii, 33 oocytes were vitrified in cryoloop. after a store time of 1-6 months theoocytes were thawed, incubated for 2 hours and subsequently the iesi was done on survivedoocytes. to verify normal fertilization of vitrified oocytes the number of pronuclei in the cytoplasmwas counted 16-18 hours after resi and good morphological quality embryos were transferred onday 2 or 3 after sperm injection. pregnancy was identified by the serum 13 heg level, checked 14days after embryo transfer.results: the present study shows that the rate of survival of vitrified human oocytes in two groupshas no significant difference (52.94% in group i versus 63.63% in group ii) but the fertilization rateof vitrified oocytes by cryoloop was greater than vitrified oocytes by conventional straws (73.7%versus 55.55% respectively). one of the embryo transfers achieved clinical pregnancy and resultedin the delivery of healthy baby.conclusion: vitrification by using cryoloop can improved the fertilization rate and developmentalcapacity of vitrified thawed oocyte.