How many mature oocytes are required at different ages to achieve one live birth?

[Tier B — no verified source for the figures] The relationship is well established in direction: the number of mature oocytes needed for one live birth rises with age, because both the proportion of euploid embryos and the efficiency of each step decline. I am deliberately not quoting oocyte-number thresholds by age band. Published estimates derive from single-centre cohorts and modelling studies with differing populations, laboratory performance and definitions, and they vary substantially between sources. Presenting a specific number as though it were a standard would repeat the pattern this audit has been correcting. What to counsel instead: Her own predicted yield per cycle from AMH or AFC — ESHRE (2026) recommends either for predicting response (strong), while noting neither predicts pregnancy or live birth. That multiple retrieval cycles are frequently needed, particularly above 38, and that this should be planned for rather than discovered. That your unit's own age-banded outcome data is more relevant than any published figure — and if you do not have it, that is worth building. ESHRE (2026) supports oocyte accumulation as a strategy: double stimulation can be used to accumulate oocytes or embryos where no fresh transfer is planned (strong). Reviewer: if you want age-banded oocyte-number targets here, they should come from your own laboratory outcomes or from a named cited study, with the population and assumptions stated.