title: Obesity and gestational weight gain: cesarean delivery and labor complications.
abstract: OBJECTIVE
  To assess the association between pre-gestational obesity and weight gain with cesarean delivery and labor complications.
  
  
  METHODS
  A total of 4,486 women 20-28 weeks pregnant attending general prenatal care clinics of the national health system in Brazil from 1991 to 1995 were enrolled and followed up through birth. Body mass index categories based on prepregnancy weight and total weight gain were calculated. Associations between body mass index categories and labor complications were adjusted through logistic regression analysis.
  
  
  RESULTS
  Obesity was present in 308 (6.9%) patients. Cesarean delivery was performed in 164 (53.2%) obese, 407 (43.1%) pre-obese, 1,045 (35.1%) normal weight and 64 (24.5%) underweight women. The relative risk for cesarean delivery in obese women was 1.8 (95% CI: 1.5-2.0) compared to normal weight women. Greater weight gain was particularly associated with cesarean among the obese (RR 4th vs 2nd weight gain quartile 2.2; 95% CI: 1.4-3.2). Increased weight at the beginning of pregnancy was associated with a significantly higher adjusted risk of meconium with vaginal delivery and perinatal death and infection in women submitted to cesarean section. Similarly, greater weight gain during pregnancy increased the risk for meconium and hemorrhage in women submitted to vaginal delivery and for prematurity with cesarean.
  
  
  CONCLUSIONS
  Pre-gestational obesity and greater weight gain independently increase the risk of cesarean delivery, as well as of several adverse outcomes with vaginal delivery. These findings provide further evidence of the negative effects of prepregnancy obesity and greater gestational weight gain on pregnancy outcomes.
authors.affiliation: Programa de Pós-Graduação em Epidemiologia, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil. lc.seligman@brturbo.com.br
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: Seligman
authors.forename: Bruce Bartholow
authors.initials: BB
authors.lastname: Duncan
authors.forename: Leandro
authors.initials: L
authors.lastname: Branchtein
authors.forename: Dea Suzana Miranda
authors.initials: DS
authors.lastname: Gaio
authors.forename: Sotero Serrate
authors.initials: SS
authors.lastname: Mengue
authors.forename: Maria Inês
authors.initials: MI
authors.lastname: Schmidt
mesh_terms: D015992:Body Mass Index; D001938:Brazil / Q000453:epidemiology; D002585:Cesarean Section / Q000706:statistics & numerical data*; D004522:Educational Status; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D009765:Obesity / Q000150:complications* / Q000453:epidemiology; D007744:Obstetric Labor Complications / Q000453:epidemiology / Q000209:etiology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology / Q000209:etiology*; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012306:Risk; D015430:Weight Gain