title: Maternal obesity in early pregnancy and risk of spontaneous and elective preterm deliveries: a retrospective cohort study.
abstract: OBJECTIVE
  We sought to determine the association between maternal body mass index and risk of preterm delivery.
  
  
  METHODS
  We assessed 187,290 women in Scotland and estimated adjusted odds ratios for spontaneous and elective preterm deliveries among overweight, obese, and morbidly obese women relative to normal-weight women.
  
  
  RESULTS
  Among nulliparous women, the risk of requiring an elective preterm delivery increased with increasing BMI, whereas the risk of spontaneous preterm labor decreased. Morbidly obese nulliparous women were at increased risk of all-cause preterm deliveries, neonatal death, and delivery of an infant weighing less than 1000 g who survived to 1 year of age (a proxy for severe long-term disability). By contrast, obesity and elective preterm delivery were only weakly associated among multiparous women.
  
  
  CONCLUSIONS
  Obese nulliparous women are at increased risk of elective preterm deliveries. This in turn leads to an increased risk of perinatal mortality and is likely to lead to increased risks of long-term disability among surviving offspring.
authors.affiliation: Department of Obstetrics and Gynaecology, Cambridge University, Rosie Maternity Hospital, Cambridge, England. gcss2@cam.ac.uk
authors.forename: Gordon C S
authors.initials: GC
authors.lastname: Smith
authors.forename: Imran
authors.initials: I
authors.lastname: Shah
authors.forename: Jill P
authors.initials: JP
authors.lastname: Pell
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Crossley
authors.forename: Richard
authors.initials: R
authors.lastname: Dobbie
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D036861:Delivery, Obstetric / Q000379:methods; D017558:Elective Surgical Procedures / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008429:Maternal Welfare; D009765:Obesity / Q000150:complications / Q000453:epidemiology*; D007752:Obstetric Labor, Premature; D016017:Odds Ratio; D050177:Overweight; D010298:Parity; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D018566:Pregnancy, High-Risk; D047928:Premature Birth / Q000453:epidemiology* / Q000209:etiology; D018570:Risk Assessment; D012307:Risk Factors; D012606:Scotland / Q000453:epidemiology