title: Differences in ovarian hormones in relation to parity and time since last birth.
abstract: OBJECTIVE
  To examine ovarian function in relation to parity and time since last birth.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Health-care program in California.
  
  
  METHODS
  346 naturally cycling women, aged 18 to 39 years.
  
  
  METHODS
  None.
  
  
  METHODS
  Mean follicular urinary estradiol metabolite concentration (E1C) (cycle days -8 to -1), mean luteal progesterone metabolite concentration (PdG) (days 0 to +10), and cycle phase lengths in ovulatory cycles.
  
  
  RESULTS
  After the women had collected daily urine samples for up to eight menstrual cycles, we measured the E1C and PdG using enzyme-linked immunoassay. The cycle phase lengths were calculated from the hormone profiles and daily diaries. Women who had given birth within the previous 3 years had lower E1C than the nulliparous women and women who last given birth >3 years earlier. Among the parous women, E1C was positively associated with the time since last birth. Women who last gave birth >3 years earlier had longer follicular phases than the nulliparous women. There were no associations between parity and PdG or luteal phase length.
  
  
  CONCLUSIONS
  Our cross-sectional data suggest that ovarian function differs in nulliparous and parous women and is positively associated with the time since last birth. Longitudinal research is needed to explore within-woman changes in ovarian function prepartum and postpartum.
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine and Dentistry, University of Rochester, Rochester, New York. Electronic address: emily_barrett@urmc.rochester.edu.
authors.forename: Emily S
authors.initials: ES
authors.lastname: Barrett
authors.affiliation: Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Parlett
authors.affiliation: Division of Environmental and Occupational Disease Control, California Department of Public Health, Richmond, California.
authors.forename: Gayle C
authors.initials: GC
authors.lastname: Windham
authors.affiliation: Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Shanna H
authors.initials: SH
authors.lastname: Swan
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000652:urine; D002140:California; D003430:Cross-Sectional Studies; D004958:Estradiol / Q000652:urine*; D005260:Female; D006801:Humans; D008597:Menstrual Cycle / Q000652:urine*; D010053:Ovary / Q000378:metabolism*; D010298:Parity; D011247:Pregnancy; D011374:Progesterone / Q000652:urine*; D013997:Time Factors; D055815:Young Adult
chemical_list: D015415:Biomarkers; D011374:Progesterone; D004958:Estradiol
keywords: Estradiol; fecundity; menstrual cycle; motherhood; ovarian function