title: Determinants of early follicular phase gonadotrophin and estradiol concentrations in women of late reproductive age.
abstract: BACKGROUND
  FSH and estradiol measured during the menstrual (basal) phase of cycles predict the success of infertility treatment; but the role of these hormones as markers for ovarian reserve in normal populations needs further study.
  
  
  RESULTS
  From a cohort study of depressed and non-depressed women, a subset of 406 non-depressed women between the ages of 36 and 45 years with spontaneous periods were selected and their concentrations and determinants of basal hormones measured at study entry, 6 and 12 months later were described. FSH and LH increased significantly over the 12 months of observation (P <or= 0.001), but considerable variation was noted in FSH and estradiol in some women monitored over the three cycles. Concentrations often varied between a pattern of low FSH, high estradiol in one cycle and high FSH, low estradiol in another. In multivariate models focusing on the maximum observed hormone concentration, significant predictors included: increasing age (P < 0.0001), smoking (P = 0.04), and shorter cycle length (P < 0.0001) during adolescence (P < 0.0001) associated with higher FSH; increasing age (P < 0.0266) and lower body mass index (P < 0.0289) associated with higher LH; and a greater number of estimated ovulatory cycles associated with higher estradiol (P < 0.0425).
  
  
  CONCLUSIONS
  Early reproductive landmarks, smoking, body weight, and factors that determine number of ovulatory cycles impact on ovarian/pituitary physiology in late reproductive life.
authors.affiliation: Obstetrics and Gynecology Epidemiology Center, Boston, MA 02115, USA. dcramer@partners.org
authors.forename: D W
authors.initials: DW
authors.lastname: Cramer
authors.forename: R L
authors.initials: RL
authors.lastname: Barbieri
authors.forename: A R
authors.initials: AR
authors.lastname: Fraer
authors.forename: B L
authors.initials: BL
authors.lastname: Harlow
mesh_terms: D000328:Adult; D000375:Aging; D000704:Analysis of Variance; D015992:Body Mass Index; D004958:Estradiol / Q000097:blood*; D005260:Female; D005298:Fertility; D005640:Follicle Stimulating Hormone / Q000097:blood*; D005498:Follicular Phase / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D008597:Menstrual Cycle; D008875:Middle Aged; D010060:Ovulation; D012098:Reproduction; D012907:Smoking; D013997:Time Factors
chemical_list: D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone