Estimating the Number of Retrieved Oocytes Needed to Obtain at Least One Euploid Blastocyst

Purpose: The objective of this study was to estimate the number of oocytes that need to be retrieved to obtain at least one euploid embryo (NOR-euploid) based on our clinic’s preimplantation genetic testing for aneuploidy (PGT-A) outcomes, stratified by maternal age. All patients underwent PGT-A due to recurrent pregnancy loss (RPL) or repeated implantation failure (RIF), which may not represent the general in vitro fertilization (IVF) population. Methods: A total of 4,440 oocyte pick-up (OPU) cycles performed for PGT-A at our clinic between April 2019 and May 2024 were retrospectively analyzed. RPL was defined as [Formula: see text] pregnancy losses; RIF was defined as [Formula: see text] transfers of morphologically good blastocysts without pregnancy. Euploidy rates were calculated based on the number of retrieved oocytes (NOR) within each maternal age group. The NOR-euploid was estimated for each age group using the inverse of the euploidy rate, and 95% confidence intervals (CIs) were calculated using the Wilson score method. Results: The euploidy rates per retrieved oocyte were as follows (95% CI): 18.1% (16.3–20.0) for [Formula: see text] years; 14.8% (13.7–16.0) for 31–32 years; 14.7% (13.8–15.7) for 33–34 years; 12.9% (11.8–14.0) for 35–36 years; 10.1% (9.3–10.9) for 37–38 years; 7.2% (6.6–7.9) for 39–40 years; 3.8% (3.3–4.3) for 41–42 years; and 1.1% (0.9–1.3) for [Formula: see text] years. The corresponding estimated NOR-euploid values were approximately 6, 7, 7, 8, 10, 14, 27, and 91, respectively. Conclusions: In women under 36 years of age, retrieving approximately 6–7 oocytes is, on average, sufficient to obtain at least one euploid blastocyst; however, individual prognosis may vary depending on multiple biological and clinical factors.