Intra-age, intercenter, and intercycle differences in chromosome abnormalities in oocytes

Objective: To determine the extent of intra-age and intercycle variations in the frequency of first polar body aneuploidy in two consecutive cycles of oocyte retrieval undertaken by the same patient within 1 year. Design: Retrospective study. Setting: Fertility centers. Patient(s): Infertile couples undergoing IVF. Intervention(s): Patients underwent two consecutive cycles of preimplantation genetic screening through first polar body biopsy within 1 year. Main Outcome Measure(s): Meiosis I aneuploidy. Result(s): A total of 226 patients underwent 452 cycles of preimplantation genetic screening. Differences within age groups were wide, with 0-100% of oocytes being chromosomally normal in all age groups. Euploidy rates between centers were significantly different (48% vs. 25%). Intercycle differences for the same patient were also wide (0-100%), but with 68.5% of patients having less than +/- 2 euploid eggs of difference between cycles. Conclusion(s): Although euploidy rate decreased on average with advancing maternal age, the high intra-age and intercenter variation in oocyte chromosome abnormalities emphasize the difficulty in estimating how many euploid oocytes a specific woman will have. This may have repercussions for fertility preservation where a defined number of eggs are currently frozen just based on maternal age. (Fertil Steril (R) 2012; 97: 935-42. (C) 2012 by American Society for Reproductive Medicine.)