Age-Based Oocyte Yield in Elective Oocyte Cryopreservation: A Retrospective Cohort Study

Background: Demand for elective oocyte cryopreservation (OC) among healthy women delaying childbearing is rising worldwide. Yet, clinicians and patients often rely on limited or indirect evidence to predict age-specific mature oocyte yield. Robust, real-world benchmarks are needed to guide expectations, estimate live birth potential, and optimize treatment planning. Methods: We retrospectively analyzed 400 healthy women aged 30-41 undergoing their first elective OC cycle between 2019 and 2023 at a large, university-affiliated fertility center. Exclusion criteria included infertility, polycystic ovary syndrome, prior ovarian surgery, and other medical indications for OC. All cycles used a standardized GnRH antagonist protocol with an initial gonadotropin dose of 300 IU/day. Only mature (metaphase II) oocytes were cryopreserved. Age-specific percentiles for total and mature oocyte yield were modeled using the General Additive Model for Location, Scale, and Shape (GAMLSS), and nomograms were developed. Results: Mean age was 35.7 years (SD 2.3). Median total and mature oocytes retrieved were 13 (IQR 9-19) and 10 (IQR 7-15), respectively. At the 50th percentile, women aged 30, 35, and 40 yielded 20, 14, and 9 total oocytes, with 15, 11, and 6 mature oocytes cryopreserved. Nomograms across percentiles illustrated a consistent, progressive decline in yield with advancing age. Conclusions: Age-based nomograms derived from real-world data can offer a clinically relevant tool to estimate the likely oocyte yield per cycle. They can help set realistic expectations, guide the number of cycles needed to meet fertility goals, and support evidence-based, shared decision-making in elective OC.