Menopause only happens to older women False: The average age at menopause, defined as one year after your last period, is 51, although many women don’t know exactly when this has occurred if they’re using hormones, such as for contraception, the perimenopause, a Mirena IUS or medicines for heavy bleeding. Half of women start symptoms several years before they reach 51, and premature ovarian insufficiency affects 1% of women, causing the menopause to occur even in your teens or 20s.