Population-based age-specific reference percentiles and Z-scores for AMH in women

Anti-Müllerian hormone (AMH) is a reliable biomarker for assessing ovarian reserve, offering insight into the quantity of a woman's remaining oocyte pool. As AMH levels naturally decline with age, establishing accurate reference values is crucial for fertility assessment and reproductive planning. While existing nomograms predominantly focus on infertile populations or small cohorts, the current study presents a comprehensive, population-based analysis of AMH levels in 5,230 women aged 25 to under 45 years. Serum samples were obtained through a central laboratory in a large tertiary hospital (Sheba Medical Center) which processes AMH tests collected primarily in the community. This unique setting provides a broadly representative sample of women from a community-based population. Utilizing these community-based serum samples measured using the Elecsys Cobas AMH assay; this cross-sectional study developed age-specific AMH percentiles and z-scores using the general additive model for location, scale and shape (GAMLSS). Participants were randomly split into a learning group (n = 4,000) and a validation group (n = 1,230), with similar median age (34.3 vs. 34.2 years, p = 0.499) and AMH (1.83 vs. 1.85 ng/mL, p = 0.584) levels. Median AMH values demonstrated a clear age-dependent decline, ranging from 3.03 ng/mL at age 25 to 0.31 ng/mL at age 44. The generated reference chart enables interpretation of AMH results in relation to age-matched peers, enhancing the clinical utility of AMH testing for counselling and decision-making in both individual and public health contexts. Importantly, this study addresses a gap in current literature by including a community-based population and avoiding the selection biases inherent in studies limited to women with infertility or polycystic ovary syndrome. The mean z-score in the validation group was approximately zero, confirming the model's robustness. These results reinforce the value of AMH as a tool for fertility assessment, while highlighting variability in AMH across populations and emphasising the need for standardised reference ranges. The newly established percentiles may support timely fertility preservation decisions and inform public health strategies aimed at fertility awareness in reproductive-aged women. As AMH testing becomes increasingly accessible, age-specific interpretation using robust population data will become essential in tailoring personalised reproductive care.