OBJECTIVETo explore the feasibility, indication and method of oocyte vitrification during the IVF - ET procedure, so as to increase the utilization of oocytes and reduce oocyte waste.

METHODSThis study included the patients whose husbands failed to provide sperm samples at the time of oocyte pickup or from whom more than 25 oocytes were obtained. With the patients' consent, some of their oocytes were subjected to cryopreservation by vitrification, and used for IVF - ET after thawed.

RESULTSTotally, 53 oocytes from 7 patients were thawed, and 44 (83.02%) survived, of which 41 M II oocytes were subjected to ICSI and 32 (72.73%) were fertilized. Thirty embryos were formed, with a cleavage rate of 93.75%. Sixteen embryos were transferred in 9 cycles, with achievement of 2 clinical pregnancies and delivery of 3 healthy babies. The implantation rate was 18.75% and the live birth rate 22.22%. Seven of the embryos were still cryopreserved.

CONCLUSIONCryopreservation of oocytes by vitrification effects satisfactory rates of survival and fertilization, and that of surplus oocytes can increase oocyte utilization and adds to the alternatives for IVF - ET.