title: "Persistence" improves the 60-day amenorrhea marker of entry to late-stage menopausal transition for women aged 40 to 44 years.
abstract: 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.
authors.affiliation: Monash University Melbourne, Australia. john.taffe@med.monash.edu.au
authors.forename: John R
authors.initials: JR
authors.lastname: Taffe
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Cain
authors.forename: Ellen S
authors.initials: ES
authors.lastname: Mitchell
authors.forename: Nancy F
authors.initials: NF
authors.lastname: Woods
authors.forename: Sybil L
authors.initials: SL
authors.lastname: Crawford
authors.forename: Siobán D
authors.initials: SD
authors.lastname: Harlow
mesh_terms: D000328:Adult; D000367:Age Factors; D000568:Amenorrhea; D015415:Biomarkers; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008593:Menopause; D011237:Predictive Value of Tests; D013997:Time Factors
chemical_list: D015415:Biomarkers