title: Body Mass Index, Overweight, and Obesity in Swedish Women Born Post-term.
abstract: BACKGROUND
  There is increasing evidence that post-term birth (≥42 weeks of gestation) is associated with adverse long-term outcomes. We assessed whether women born post-term displayed increased risk of overweight and obesity in adulthood.
  
  
  METHODS
  Data were collected at first antenatal visit (~10-12 weeks of gestation) on singleton Swedish women aged ≥18 years in 1991-2009 (mean age 26.1 years), who were born post-term (n = 27 153) or at term (37-41 weeks of gestation; n = 184 245). Study outcomes were evaluated for continuous associations with gestational age. Stratified analyses were carried out comparing women born post-term or at term. Analyses were also run with a 2-week buffer between groups to account for possible errors in gestational age estimation, comparing women born very post-term (≥43 weeks of gestation; n = 5761) to those born within a narrower term window (38-40 weeks of gestation; n = 130 110).
  
  
  RESULTS
  Increasing gestational age was associated with greater adult weight and body mass index (BMI). Stratified analyses showed that women born post-term were 0.5 kg heavier and had BMI 0.2 kg/m(2) greater than those born at term. Differences were more marked between women born very post-term (≥43 weeks) vs. a narrower term group (38-40 weeks): 1.0 kg and 0.3 kg/m(2) . The adjusted relative risks of overweight/obesity and obesity in women born very post-term were 1.13 and 1.12 times higher, respectively, than in those born at term.
  
  
  CONCLUSIONS
  Post-term birth is associated with greater BMI and increased risk of overweight and obesity in adulthood, particularly among women born ≥43 weeks of gestation.
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand.
authors.forename: José G B
authors.initials: JG
authors.lastname: Derraik
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
authors.forename: Maria
authors.initials: M
authors.lastname: Lundgren
authors.affiliation: Liggins Institute, University of Auckland, Auckland, New Zealand.
authors.forename: Wayne S
authors.initials: WS
authors.lastname: Cutfield
authors.affiliation: Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Ahlsson
mesh_terms: D000328:Adult; D001724:Birth Weight; D015992:Body Mass Index; D002657:Child Development; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007233:Infant, Postmature; D009765:Obesity / Q000453:epidemiology* / Q000209:etiology; D050177:Overweight / Q000453:epidemiology* / Q000209:etiology; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D011446:Prospective Studies; D018570:Risk Assessment; D013548:Sweden / Q000453:epidemiology; D015430:Weight Gain
keywords: adult; body mass index; females; gestational age; obesity; overweight; prolonged gestation