Pregnancies and births after oocyte cryopreservation

Objective: To determine the potential of oocyte cryopreservation techniques. Design: Retrospective data analysis. Setting: A tertiary infertility center. Patient(s): Sixty-eight patients (29 to 37 years of age) undergoing assisted reproduction procedures for infertility problems. Intervention(s): 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. Main Outcome Measure(s): Rates of survival after thawing, fertilization after intracytoplasmic sperm injection, cleavage, implantation, and pregnancy. Result(s): 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. Conclusion(s): 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. (C) 2004 by American Society for Reproductive Medicine.