Morris DH, Jones ME, Schoemaker MJ, Ashworth A, Swerdlow AJ. Secular trends in age at menarche in women in the UK born 1908–93: results from the Breakthrough Generations Study. Paediatric and Perinatal Epidemiology 2011; 25: 394–400.
Menarcheal age decreased over time in Western countries until cohorts born in the mid-20th century. It then stabilised, but limited data are available for recent cohorts. Menarche data were collected retrospectively by questionnaire in 2003–10 from 94 170 women who were participating in the Breakthrough Generations Study, aged 16–98 years, born 1908–93 and resident in the UK. Average menarcheal age declined from women born in 1908–19 (mean = 13.5 years) to those born in 1945–49 (mean = 12.6 years). It was then stable for several birth cohorts, but resumed its downward trend in recent cohorts (mean = 12.3 years in 1990–93 cohort). Trends differed between socio-economic groups, but the recent decline was present in each group. In conclusion, menarcheal age appears to have decreased again in recent cohorts after a period of stabilisation.