Menarcheal age in Norway in the 19th century: a re-evaluation of the historical sources.

A fall in the age of menarche during the last fifty years is well documented from many parts of the world, among them Norway. Tanner says that this trend can be extended back at least to the middle of the last century, and he uses Norwegian sources to support this hypothesis. Re-examination of these Norwegian sources indicates that there was no fall at all during the ninetheenth century, and that the age at menarche was constant at approximately 16.0 years for the lower social classes throughout this period. It is also suggested that the age at menarche was constant at approximately 14 years for the higher social classes.