Elective Cryopreservation of all 2PN Oocytes after in-vitro Maturation: a Prospective, Clinical Pilot Study

摘要

Purpose: To evaluate the effectiveness of temporally splitting in-vitro maturation and embryo transfer by elective cryopreserving of all 2PN oocytes after in–vitro maturation (IVM). Methods: This one armed clinical cohort study was prospectively performed. Twenty eight patients fulfilled the inclusion criteria after AFC assessment by transvaginal sonography. Patients were retrospectively divided into (primed) group which received a low dose of gonadotropin stimulation, and (non-primed) group which received no medication. IVM in combination with cryopreservation by vitrification of all 2PN oocytes was investigated for all included patients. Results: Mean number of cumulus-oocyte complex (COC) was found to be 9 ± 8.4 and the average number of matured oocytes was 4.1 ± 4.8. After vitrification and thawing, the overall survival rate was 92.9%. The overall clinical pregnancy rate per WHAT was 17.9%. The cumulative clinical and ongoing pregnancy rate per patient with at least one embryo transfer (ET) performed was 23.8% and 12.1-41.6% for 95% confidence interval (CI). No differences was found for in outcome between primed and non-primed patients in positive hCG results. Conclusions: The addition of electively cryopreservation by vitrification of all 2PN stage embryos to IVM technique applied for high AFC in patients undergoing IVF treatment in both primed and natural cycles results in an acceptable chance of ongoing pregnancy.