title: Effect of oral contraceptives on weight and body composition in young female runners.
abstract: OBJECTIVE
  To examine the effect of oral contraceptives (OC) on body weight, fat mass, percent body fat, and lean mass in young female distance runners.
  
  
  METHODS
  The study population consisted of 150 female competitive distance runners aged 18-26 yr who had participated in a 2-yr randomized trial of the effect of the OC Lo/Ovral (30 microg of ethinyl estradiol and 0.3 mg of norgestrel) on bone health. Weight and body composition were measured approximately yearly by balance beam scales and dual-energy x-ray absorptiometry, respectively.
  
  
  RESULTS
  Women randomized to the OC group tended to gain slightly less weight (adjusted mean difference (AMD) = -0.54 +/- 0.31 kg.yr, P = 0.09) and less fat (AMD = -0.35 +/- 0.25 kg.yr, P = 0.16) than those randomized to the control group. OC assignment was associated with a significant gain in lean mass relative to controls among eumenorrheic women (those who had 10 or more menstrual cycles in the year before baseline; AMD = 0.77 +/- 0.17 kg.yr, P < 0.0001) but not among women with fewer than 10 menstrual cycles in that year (AMD = 0.02 +/- 0.35 kg.yr, P = 0.96). Treatment-received analyses yielded similar results.
  
  
  CONCLUSIONS
  This randomized trial confirms previous findings that OC use does not cause weight or fat mass gain, at least among young female runners. Our finding that this OC is associated with lean mass gain in eumenorrheic runners, but not in those with irregular menses, warrants examination in other studies.
authors.affiliation: Division of Preventive and Behavioral Medicine, University of Massachusetts Medical School, Worcester, MA, USA. LizGray79@Hotmail.com
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Procter-Gray
authors.forename: Kristin L
authors.initials: KL
authors.lastname: Cobb
authors.forename: Sybil L
authors.initials: SL
authors.lastname: Crawford
authors.forename: Laura K
authors.initials: LK
authors.lastname: Bachrach
authors.forename: Annapoorna
authors.initials: A
authors.lastname: Chirra
authors.forename: Maryfran
authors.initials: M
authors.lastname: Sowers
authors.forename: Gail A
authors.initials: GA
authors.lastname: Greendale
authors.forename: Jeri W
authors.initials: JW
authors.lastname: Nieves
authors.forename: Kyla
authors.initials: K
authors.lastname: Kent
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Kelsey
mesh_terms: D000222:Adaptation, Physiological; D000273:Adipose Tissue; D000293:Adolescent; D000328:Adult; D000568:Amenorrhea / Q000378:metabolism; D001823:Body Composition / Q000187:drug effects*; D001835:Body Weight / Q000187:drug effects*; D003276:Contraceptives, Oral / Q000494:pharmacology*; D017079:Exercise Tolerance / Q000187:drug effects; D005260:Female; D006801:Humans; D009839:Oligomenorrhea / Q000378:metabolism; D012420:Running / Q000502:physiology*; D055815:Young Adult
chemical_list: D003276:Contraceptives, Oral