Abstract
Mean ages were 12.9 years at menarche, 25.7 years at first birth, and 50.5 years at natural menopause, with significant between-study heterogeneity. A linear trend was observed across birth year for mean age at menarche. The prevalence of nulliparity rose progressively from 14% of women born from 1940 49 to 22% of women born 1970 84; similarly, the mean age at first birth rose from 24.8 to 27.3 years. Women with higher education levels had fewer children, later first birth, and later menopause than women with lower education levels.