Is there a secular trend in age of menopause?

A review of the difficulties encountered in analyzing a secular trend in age of menopause is given with emphasis on the advantages and disadvantages of the recollective and "status quo" methods. It is suggested that no methodology except that which is prospective will give accurate ages of menopause. Accepting this given, a review of the literature from 1864 to 1964 is undertaken, that suggests there may be a secular trend in Denmark, England, France, Germany, Russia and the USA. This must, however, be corroborated by longitudinal, cross cultural, generational research of mothers' and daughters' ages at menopause, or at least, cohort analysis of specific populations.