Probability of finding at least one euploid embryo and the euploidy rate according to the number of retrieved oocytes and female age using FISH and array CGH

Abstract

Objective: To assess the probability of finding at least one euploid embryo (POE) and euploidy rate in preimplantation genetic screening (PGS) cycles for aneuploidy testing with fluorescent in situ hybridization (FISH) and array comparative genomic hybridization (aCGH) based on the number of retrieved oocytes after adjustment for age. Design: Retrospective data analysis. Setting: Private in vitro fertilization center in a general hospital, Istanbul, Turkey. Patient(s): In this study, 1412 couples with 1739 cycles were included. Intervention(s): Embryo biopsy at cleavage stage or trophectoderm biopsy analyzed by FISH or aCGH techniques. Main outcome measure(s): Probability of finding at least one euploid embryo for transfer and euploidy rate according to retrieved oocytes after adjustment for age. Result(s): Estimated probabilities of finding at least one euploid embryo were plotted based on age and number of retrieved oocytes. When controlled for age, the POE increased with each additional oocyte retrieved (OR 1.11, 95% CI 1.08–1.14), but the euploidy rate did not. When retrieved oocytes were subgrouped, we found that the odds of finding at least one euploidy embryo were highest when 16–20 oocytes were retrieved compared to 1–5 oocytes with both FISH (OR 8.62, 95% CI 4.67–15.93) and aCGH (OR 2.78, 95% CI 1.07–7.21). However, the chances did not increase with the retrieval of more than 20 oocytes. Conclusion(s): The estimated probabilities of finding at least one transferrable embryo would enable more accurate counselling of patients based on age and the number of retrieved oocytes. As the highest estimates for finding one euploidy embryo were achieved with 15-20 oocytes, deciding the best protocol for ovarian stimulation to achieve the maximum number of oocytes for retrieval based on the patients age and ovarian reserve would be of crucial importance.