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.