title: Caesarean delivery, caesarean delivery on maternal request and childhood overweight: a Chinese birth cohort study of 181 380 children.
abstract: What is already known about this subject Both rates of caesarean section and childhood overweight have been steadily increasing over the past decade in many parts of the world. Caesarean delivery on maternal request contributes remarkably to the rising trend of caesarean births. A few small-scale studies suggest that caesarean section may be associated with later overweight and obesity, whereas little is known about the impact of caesarean delivery on maternal request. What this study adds Caesarean section is associated with an increased risk of childhood overweight. Children born by caesarean delivery on maternal request are also more likely to be overweight. The strength of the caesarean-overweight association is modest.
  
  
  OBJECTIVE
  To assess the impact of caesarean delivery including non-medically indicated maternal request caesarean delivery on childhood overweight.
  
  
  METHODS
  We conducted a prospective investigation of a Chinese birth cohort involving 181 380 children, who were born during 1993-1996 to mothers registered in a perinatal care surveillance system and whose weight and height were measured in 2000. Information on delivery mode and covariates was obtained from the surveillance system. Overweight was defined according to the International Obesity Task Force body mass index (BMI) cutoffs. Multivariable logistic regression was used to estimate adjusted odds ratios. Stratified analyses were done to test whether the association between caesarean section and overweight persisted across subgroups.
  
  
  RESULTS
  The adjusted odds ratio of overweight for children born by caesarean compared with vaginal delivery was 1.13 [95% confidence interval {CI}: 1.08, 1.18]. The association persisted in subgroups stratified by gender, maternal education, maternal BMI, weight gain during pregnancy and child birthweight (all P values for interaction test ≥0.30). The adjusted odds ratio of overweight for children born by non-medically indicated caesarean delivery compared with vaginal delivery was 1.18 (95% CI: 1.00, 1.41).
  
  
  CONCLUSIONS
  Caesarean delivery including non-medically indicated maternal request caesarean delivery compared with vaginal delivery modestly increases childhood overweight risk.
authors.affiliation: Institute of Reproductive and Child Health, Ministry of Health Key Laboratory of Reproductive Health, School of Public Health, Peking University Health Science Center, Beijing, China; Department of Epidemiology and Biostatistics, School of Public Health, Peking University Health Science Center, Beijing, China.
authors.forename: H
authors.initials: H
authors.lastname: Li
authors.forename: R
authors.initials: R
authors.lastname: Ye
authors.forename: L
authors.initials: L
authors.lastname: Pei
authors.forename: A
authors.initials: A
authors.lastname: Ren
authors.forename: X
authors.initials: X
authors.lastname: Zheng
authors.forename: J
authors.initials: J
authors.lastname: Liu
mesh_terms: D000328:Adult; D001724:Birth Weight; D015992:Body Mass Index; D002585:Cesarean Section / Q000009:adverse effects* / Q000706:statistics & numerical data*; D002681:China / Q000453:epidemiology; D036861:Delivery, Obstetric / Q000706:statistics & numerical data*; D017558:Elective Surgical Procedures; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D016015:Logistic Models; D008297:Male; D009035:Mothers; D016017:Odds Ratio; D063766:Pediatric Obesity / Q000453:epidemiology* / Q000209:etiology; D011247:Pregnancy; D011446:Prospective Studies; D012307:Risk Factors
keywords: Birth cohort; caesarean delivery; children; overweight.