4. Age at menarche: international perspectives

From both social and medical perspectives, menarche is often considered the central event of female puberty as it signals the possibility of fertility. The aim of this report is to review the menarcheal age in different countries and consider the factors that influence it. We also review the implications of early or late menarcheal age on a young woman’s life. The improvement of socioeconomic conditions during the 20 th century resulted in an earlier onset of puberty in children, indicated by the fall of the age at menarche (AAM). However, there are reports from industrialised countries that this trend has been levelling off. There is high variability due to the many factors (i.e. neuroendocrin, genetic, socioeconomic and environmental) that act synergistically on the onset of menstruation. Menarcheal age has important health implications, as early menarche is associated with more cardiovascular incidents and other ailments, including cancer mortality, especially of the breast. Late menarche is associated with osteoporosis and an increased fracture risk. Moreover, early menarche has been related to anxiety symptoms, depression, premature intercourse and violent behaviour. In general, mean ages at menarche ≤13.0 years are recorded in central-southern Europe, Russia, China, Japan, many countries of the Americas, Australia and New Zealand, while higher mean menarcheal ages are found in Africa, many Asian countries and many developing and geographically disadvantaged countries (i.e. those at high altitudes). The AAM in Asian countries is similar to that of Mediterranean girls. More and bigger studies involving a larger population base and considering the effecting factors are required to predict menarcheal ages more accurately.