Embryo development and gestation using fresh and vitrified oocytes

BACKGROUND The objective of this study was to compare the gestational results obtained with vitrified/thawed oocytes by a novel vitrification method (Vitri-ingá) to results obtained with fresh oocytes. METHODS A total of 125 IVF-ET procedures carried out over 2008 were analysed, in which 79 patients received embryos from fresh oocytes (Group 1), and 46 patients received embryos from vitrified/thawed oocytes using Vitri-ingá (Group 2). Fresh and vitrified/thawed oocytes were fertilized and embryos were transferred. Fertilization, pregnancy and implantation rates were compared. RESULTS Vitrified oocytes presented a survival rate of 84.9%. Fertilization, pregnancy and implantation rates showed no statistically significant differences between fresh and cryopreserved/thawed groups (81.3, 51.9, 21.3% and 80.8, 45.6 and 14.9%, respectively). Only the average number of blastomeres in Group 1 (6.86 ± 2.07) was significantly higher than in Group 2 (6.35 ± 2.26; P = 0.010). CONCLUSIONS Despite some differences in the patient groups, the clinical results of this study demonstrated that the Vitri-ingá method preserves the potential of human vitrified oocytes for fertilization and further development.