OBJECTIVE: The ReSTAGE collaboration evaluated four menstrual markers of entry to late-stage menopausal transition. The aim of this study was to assess the additional usefulness of "persistence" in relation to a clinically accessible menstrual marker of late menopausal transition, taking age into account. METHODS: In this study, a secondary analysis of menstrual calendar data in two ReSTAGE-collaborating studies with comparatively low age at beginning of menstrual calendar observation was performed. RESULTS: Sixty days of amenorrhea is as useful for predicting time to the final menstrual period as the currently accepted 90-day marker for women older than 45 years. For those aged between 40 and 44 years, recurrence of the 60-day marker within the next 10 cycles is a better indicator than a single occurrence of the 60-day marker or the 90-day marker. CONCLUSIONS: Sixty-day amenorrhea is as reliable a marker of late menopausal transition as the traditional 90-day marker for women older than 45 years. For those aged 40 to 44 years, keeping menstrual records to check for a recurrence of the 60-day marker will be useful.

OBJECTIVE: Criteria for staging the menopausal transition are not established. This article evaluates five bleeding criteria for defining early transition and provides empirically based guidance regarding optimal criteria. DESIGN/SETTING: Prospective menstrual calendar data from four population-based cohorts: TREMIN, Melbourne Women's Midlife Health Project (MWMHP), Seattle Midlife Women's Health Study (SMWHS), and Study of Women's Health Across the Nation (SWAN) with annual serum FSH from MWMHP and SWAN. PARTICIPANTS: 735 TREMIN, 279 SMWHS, 216 MWMHP, and 2270 SWAN women aged 35-57 at baseline who maintained menstrual calendars. MAIN OUTCOME MEASURE(S): Age at and time to menopause for: standard deviation >6 and >8 days, persistent difference in consecutive segments >6 days, irregularity, and >or=45 day segment. Serum FSH concentration. RESULT(S): Most women experienced each of the bleeding criteria. Except for a persistent >6 day difference that occurs earlier, the criteria occur at a similar age and at approximately the same age as late transition in a large proportion of women. FSH was associated with all proposed markers. CONCLUSION(S): The early transition may be best described by ovarian activity consistent with the persistent >6 day difference, but further study is needed, as other proposed criterion are consistent with later menstrual changes.

CONTEXT: The current criterion for onset of late menopausal transition is amenorrhea of 90 d or more. The Stages of Reproductive Aging Workshop proposed alternative criteria based on a shorter period of amenorrhea. Empirical data comparing proposed criteria are not available. OBJECTIVE: This paper evaluates the several bleeding criteria that served as the basis of these recommendations. The goal was to provide empirically based guidance regarding which bleeding criterion may be optimal for widespread application in clinical and research settings. DESIGN/SETTING: The study used prospective menstrual calendar data from four community and population-based cohort studies: TREMIN, Melbourne Women's Midlife Health Project, Seattle Midlife Women's Health Study, and Study of Women's Health Across the Nation. PARTICIPANTS: The study included 735 TREMIN, 279 Seattle Midlife Women's Health Study, 216 Melbourne Women's Midlife Health Project, and 2270 Study of Women's Health Across the Nation women aged 35-57 yr at baseline who contributed 10 menstrual cycles or more. MAIN OUTCOME MEASURE(S): The main measures were the frequency of and median age at occurrence and time from occurrence to final menstrual period (FMP) for four criteria: skipped segment, 10-segment running range, 60- and 90-d amenorrhea. RESULTS: A skipped segment, 10-segment running range greater than 42 d and 60-d amenorrhea identify a similar time in women's reproductive lives. The latter two identify the exact same date in two thirds of women. All three criteria occur in a greater proportion of women than the 90-d criterion and are equally predictive of the FMP, although they occur 1-2 yr earlier. CONCLUSIONS: These findings support the recommendation of the Stages of Reproductive Aging Workshop that 60 d of amenorrhea be used to define onset of the late menopausal transition.