Pregnancies and births after oocyte cryopreservation

To determine the potential of oocyte cryopreservation techniques. Retrospective data analysis. A tertiary infertility center. Sixty-eight patients (29 to 37 years of age) undergoing assisted reproduction procedures for infertility problems. Oocytes from women treated for infertility were cryopreserved with a slow cooling/rapid thawing protocol in which 1,2 propanediol and sucrose were used as cryoprotectants. Eighty-six thawing cycles were performed. Rates of survival after thawing, fertilization after intracytoplasmic sperm injection, cleavage, implantation, and pregnancy. We treated 68 patients through 86 thawing cycles.. Seven hundred thirty-seven oocytes were thawed, and 59 transfer cycles were performed. The survival rate was 37%. The fertilization and cleavage rates were 45.4% and 86.3%, respectively. A total of 15 clinical pregnancies were achieved with pregnancy rates of 25.4% per transfer and 22% per patient. There were three miscarriages, resulting in an abortion rate of 20%. Seventeen of the 104 transferred embryos implanted, corresponding to an implantation rate of 16.4%. Thirteen babies were born, 8 females and 5 males. Statistically significant results were obtained for fertilization, cleavage, and pregnancy rates. Our results show oocyte cryopreservation may represent an alternative to embryo storage in selected cases.