title: Defining menopause status: creation of a new definition to identify the early changes of the menopausal transition.
abstract: OBJECTIVE
  Several menopausal staging definitions are currently being used in ongoing studies designed to identify changes occurring during menopause. The objective of this study was to determine which definition captures the earliest hormonal changes in the menopausal transition.
  
  
  METHODS
  In this prospective cohort study, women aged 35 to 47 years were followed for 5 years. Women were classified as premenopausal, early transition, late transition, and postmenopausal by 2 different menopausal staging systems defined by bleeding patterns. Definitions from the Study of Women Health Across the Nation (SWAN) and Stages of Reproductive Aging Workshop (STRAW) were compared. A new menopausal staging system (PENN-5) was also developed with five groups rather than four to distinguish among women with more subtle changes in cycle length. For each staging system, a linear regression model was created comparing mean hormone values (inhibin B, FSH, LH, E2) and menopausal stages at each assessment. Race, body mass index, cycle day, smoking, and follow-up time were included in the model.
  
  
  RESULTS
  Statistically significant differences in mean inhibin B and FSH levels, but not estradiol levels, were detected between the earliest menopausal stages of each definition. Significant differences in LH values were detected among the earliest stages of the SWAN and STRAW definitions, but not the PENN-5 definition.
  
  
  CONCLUSIONS
  Subtle changes in menstrual cycle length reflect significant changes in inhibin B and FSH levels during the menopausal transition. Therefore, it appears that subtle changes in bleeding pattern may be helpful in identifying the earliest hormonal changes during menopausal transition.
authors.affiliation: Department of Obstetrics/Gynecology, University of Pennsylvania School of Medicine, Philadelphia, PA, USA. cgracia@obgyn.upenn.edu
authors.forename: Clarisa R
authors.initials: CR
authors.lastname: Gracia
authors.forename: Mary D
authors.initials: MD
authors.lastname: Sammel
authors.forename: Ellen W
authors.initials: EW
authors.lastname: Freeman
authors.forename: Hui
authors.initials: H
authors.lastname: Lin
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Langan
authors.forename: Shiv
authors.initials: S
authors.lastname: Kapoor
authors.forename: Deborah B
authors.initials: DB
authors.lastname: Nelson
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D007265:Inhibins / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008499:Medical Records; D008593:Menopause; D008597:Menstrual Cycle / Q000097:blood / Q000502:physiology*; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; C422364:inhibin B; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone