AGE AT MENARCHE AND AN ANALYSIS OF SECULAR TRENDS IN MENARCHEAL AGE OF SOUTH-AFRICAN URBAN AND RURAL BLACK FEMALES

Age at menarche was estimated using status quo techniques on a sample of 230 rural South African females aged 11 to 17 years. Mean age of menarche was 14.03 years (SD = 1.25 years). Compared with contemporary rural and well‐off urban samples, these females experienced menarche 0.6 years earlier than did the rural sample and 0.8 years later than the well‐off urban group. Data from 11 previously reported studies of menarcheal age in urban and rural girls were analyzed with these data to determine the existence and magnitude of secular trends and whether rates differed between urban and rural environments. Regression analysis demonstrated a clear secular trend in both urban and rural females since 1943. Menarcheal age decreased at a rate of 0.34, 0.73, and 0.46 years per decade for rural, urban, and combined groups, respectively. The decline in menarcheal age over the last 40 years is thought to be due to improving socioeconomic conditions, but differences between urban and rural groups remain. Within rural groups there appears to be considerable variation in menarcheal age. Copyright © 1991 Wiley‐Liss, Inc., A Wiley Company