title: Longitudinal changes in maternal serum leptin concentrations, body composition, and resting metabolic rate in pregnancy.
abstract: OBJECTIVE
  We sought to evaluate the longitudinal changes in maternal serum leptin concentrations, body composition, and resting metabolic rate during pregnancy.
  
  
  METHODS
  Ten women were evaluated before pregnancy, in early pregnancy (12 to 14 weeks), and in late pregnancy (34 to 36 weeks). Leptin concentrations were measured by radioimmunoassay, body composition with hydrodensitometry with adjustment for total body water, and resting metabolic rate by use of indirect calorimetry.
  
  
  RESULTS
  Using analysis of variance with repeated measures from pregravid to late pregnancy, a 66% increase (mean +/- SD) was found in leptin concentrations (in nanograms per milliliter) (before pregnancy, 25.4 +/- 19.9; in early pregnancy, 37.5 +/- 26.2; and in late pregnancy, 38.4 +/- 27.3, p = 0.003); a 9% increase in body fat (in kilograms) (before pregnancy, 29.4 +/- 15.7; in early pregnancy, 28.7 +/- 14.0; in late pregnancy, 31.4 +/- 14.6; p = 0.04); a 28% increase in oxygen consumption (in milliliters of oxygen per minute) (before pregnancy, 221.2 +/- 29.5; in early pregnancy, 230.4 +/- 42.9; in late pregnancy, 285.3 +/- 51.9; p < 0.0001); and a 9% increase in oxygen consumption (milliliters of oxygen per kilogram per minute) (before pregnancy, 3.02 +/- 0.43; in early pregnancy, 3.05 +/- 0.30; in late pregnancy, 3.31 +/- 0.37, p = 0.002) with advancing gestation. A significant positive correlation was present between leptin and body fat before pregnancy (r = 0.90, p < 0.0001), in early pregnancy (r = 0.91, p < 0.0001), and in late pregnancy (r = 0.87, p = 0.0005) and between leptin and oxygen consumption before pregnancy (r = 0.80, p = 0.004), in early pregnancy (r = 0.92, p < 0.0001), and in late pregnancy (r = 0.62, p = 0.06). When oxygen consumption was adjusted for maternal and fetal tissue mass, a significant negative correlation was found between leptin and oxygen consumption before pregnancy (r = -0.96, p < 0.0001), in early pregnancy (r = -0.80, p = 0.0034), and in late pregnancy (r = -0.70, p = 0.02).
  
  
  CONCLUSIONS
  We conclude that leptin increases significantly during early pregnancy before any major changes in body fat and resting metabolic rate. These data suggest that pregnancy represents a leptin-resistant state.
authors.affiliation: Department of Reproductive Biology, Case Western Reserve University at MetroHealth Medical Center, Cleveland, Ohio, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Highman
authors.forename: J E
authors.initials: JE
authors.lastname: Friedman
authors.forename: L P
authors.initials: LP
authors.lastname: Huston
authors.forename: W W
authors.initials: WW
authors.lastname: Wong
authors.forename: P M
authors.initials: PM
authors.lastname: Catalano
mesh_terms: D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D005260:Female; D005865:Gestational Age; D006801:Humans; D020738:Leptin; D010101:Oxygen Consumption; D011247:Pregnancy / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*
chemical_list: D020738:Leptin; D011506:Proteins