Secular trend in age at menarche in Egypt: a national study

Abstract Age at menarche (AAM) is an important marker of female pubertal development and population health. Secular declines in AAM have been reported worldwide, but national data from Egypt remain limited. To evaluate secular trends in AAM among Egyptian females and identify factors associated with menarcheal timing. A national cross-sectional study was conducted among Egyptian females aged ≥ 10 years from multiple governorates. Data on AAM, residence, parental education, maternal employment, season of birth, birth order, and retrospectively self-reported weight status at menarche were collected using a structured questionnaire. Participants were classified into six birth cohorts to assess secular trends. Associations between AAM and potential determinants were analyzed using appropriate statistical methods. A total of 3,643 Egyptian females aged ≥ 10 years were included. A significant secular decline in AAM was observed across successive birth cohorts, with an approximately one-year reduction between the oldest and youngest cohorts ( p < 0.001). Earlier AAM was significantly associated with urban residence and higher parental education. Significant regional variation was observed across governorates. In contrast, season of birth and maternal employment were not significantly associated with AAM. Conclusions : Egyptian females have experienced a continuing decline in AAM, consistent with global trends toward earlier pubertal onset. Urbanization and socioeconomic factors were associated with earlier menarche. Ongoing monitoring of pubertal timing is warranted. What is Known: • A secular decline in age at menarche has been reported globally. • Nutritional and socioeconomic transitions influence pubertal timing. What is New: • This is among the first nationally distributed Egyptian studies evaluating secular trends in age at menarche. • Egyptian females demonstrated an approximately one-year decline in age at menarche across successive birth cohorts; earlier menarche was associated with urban residence and higher parental education in this Egyptian cohort.