Monitoring reproductive aging in a 5-year prospective study: aggregate and individual changes in steroid hormones and menstrual cycle lengths with age

Abstract

Aggregate-level analyses show general changes in steroid hormones and cycle length but cannot show variation within and across women. Individuals' cycle lengths were too variable to predict hormone levels. Clinicians should obtain more data on individual women's hormonal patterns when determining fertility or menopause treatments.

Monitoring reproductive aging in a 5-year prospective study

“…Participant and nonparticipant data were presented previously. 32 For this analysis, 67 women were postmenopausal for the entirety of their participation in the BIMORA project, and 89 women had at least one menstrual bleed during the project.…”

“…Specimens were self-collected and shipped to the laboratory for analysis. 32 Urinary levels of the ALH and AFSH subunits were assayed in duplicate using sandwich immunoenzymometric assays (IEMA) 34 ; they were highly correlated with serum LH and FSH (intact) results. 34 The urinary LH IEMA measured total free ALH; all urine specimens were heated for 2 minutes before assay to dissociate intact LH into its free A and > subunits.…”

“…32 A total of 156 women who were participants in TREMIN participated in the BIMORA project. TREMIN is an ongoing study of menstruation and health begun in the 1930s by Dr. Alan Treloar at the University of Minnesota; TREMIN/ BIMORA participants were white, college-educated women of mostly northern European ancestry.…”

“…In a previous analysis, 32 we presented data on steroid hormones based on the Biodemographic Models of Reproductive Aging (BIMORA) project, a 5-year, prospective study for which participants provided daily urine specimens and menstrual bleeding data for 6-month intervals in each year. BIMORA participants were college-educated, midwestern American, white women who also participated in the TREMIN Research Program on Women`s Health.…”

Individual variation in endocrine systems: moving beyond the ‘tyranny of the Golden Mean’

“…At longer time scales, interindividual variation in age-dependent changes in hormone levels is also evident, e.g. in human females, Ferell et al (2005) showed that population-level analyses of steroid hormone and menstrual cycle changes do not accurately predict relationships within and among individual women. Thus, the principles of homeostasis notwithstanding, large (5-to 10-fold) inter-individual variation is the norm for hormone titres and some endocrine-mediated traits at all temporal scales.…”