Menarcheal age in Oslo during the last 140 years

Abstract

Data from maternity clinics was used to study the trend in menarcheal age among girls born in Oslo after 1840. The investigation was based on recordings from approximately 50 women from each year. The women were divided into social categories according to their own or their husband''s occupation. The results show a trend toward earlier maturation within the working class, which is characterized by 2 periods of rapid fall in menarcheal age. The 1st period covers women born between 1860-1880, and shows a fall in menarcheal age from about 15.6-14.6 yr. During the 2nd period of rapid fall, which covers women born between 1905-1940, the menarcheal age was reduced from about 14.6-13.3 yr. The age at menarche was stable at about 13.3 yr for women born after 1940. These results contrast with those of some earlier studies of the menarcheal age in Norway. The discrepancies between these investigations disappear when the same computational methods and the same interpretation of the age recordings are used.