title: Prepregnancy body mass index and the length of gestation at term.
abstract: OBJECTIVE
  The purpose of this study was to examine the relationship between prepregnancy body mass index (BMI) and length of gestation at term.
  
  
  METHODS
  This was a retrospective study of 9336 births at the University of California, San Francisco, at > or = 37 weeks' gestation. We performed univariate and multivariable analyses of the associations between prepregnancy BMI and length of gestation (> or = 40, > or = 41, and > or = 42 weeks' gestation).
  
  
  RESULTS
  Overweight women were more likely to deliver at > or = 40, > or = 41, and > or = 42 weeks' gestation than were women who were underweight or normal weight. In multivariable analyses, higher prepregnancy BMI was associated with higher risk of progressing past 40 weeks. Obese women had 69% higher adjusted odds of reaching 42 weeks' gestation, compared with women of normal prepregnancy BMI (adjusted odds ratio, 1.69; 95% confidence interval, 1.23-2.31).
  
  
  CONCLUSIONS
  Higher BMI is associated with prolonged gestation at term. Achieving optimal BMI before conception may reduce the risk of postterm pregnancy and its associated complications.
authors: Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, School of Medicine, San Francisco, CA, USA.
authors: Naomi E
authors: NE
authors: Stotland
authors: A Eugene
authors: AE
authors: Washington
authors: Aaron B
authors: AB
authors: Caughey
mesh_terms: D000328:Adult; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D015999:Multivariate Analysis; D011247:Pregnancy; D012189:Retrospective Studies