Age at menarche and age-adjusted anti-Müllerian hormone level among women of childbearing age in China

Trends toward earlier age at menarche, the starting point in women’s reproductive lifespan, have been observed globally. Whether an earlier age at menarche influences Anti-Müllerian hormone (AMH), a clinical indicator of ovarian reserve, remains unclear due to a lack of community-based data. This nationwide cross-sectional survey was carried out in China’s 15 provinces from May 2019 to April 2021, utilizing a multistage stratified sampling method to ensure sample representativeness and containin