title: Cesarean delivery and risk of inflammatory bowel disease: a systematic review and meta-analysis.
abstract: OBJECTIVE
  It has been considered that cesarean delivery is a risk factor for the two subtypes of inflammatory bowel diseases (IBDs): Crohn's disease (CD) and ulcerative colitis (UC). The aim of this meta-analysis was to examine the relationship between cesarean delivery and the development of IBD.
  
  
  METHODS
  We searched the articles retrieved by PubMed, MEDLINE and EMBASE databases to identify observational studies regarding the relationship between cesarean section and the development of CD and/or UC. Pooled odds ratios were calculated for each relationship.
  
  
  RESULTS
  Nine studies evaluated the potential association between cesarean delivery and the development of IBD and met all of our inclusion criteria. The pooled data from six included studies indicated cesarean delivery was a risk factor for CD (95% confidence interval [CI]: 1.12-1.70; p = 0.003). Likewise, we observed a positive association between cesarean delivery and pediatric CD (95% CI: 1.06-1.35; p = 0.005). However, results from the four included studies for UC indicated the rate of cesarean section in UC patients was not higher than that of control subjects (95% CI: 0.87-1.32; p = 0.54). Overall, we did not observe a positive relationship between cesarean delivery and IBD (95% CI: 0.99-1.30; p = 0.08).
  
  
  CONCLUSIONS
  Results of this meta-analysis support the hypothesis that cesarean delivery was associated with the risk of CD but not of UC. The total rate of cesarean delivery of IBD patients was similar with that of control subjects.
authors.affiliation: Department of General Surgery, Jinling Hospital, Medical School of Nanjing University , No. 305 East Zhongshan Road, Nanjing , PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Yun
authors.initials: Y
authors.lastname: Tian
authors.forename: Weiming
authors.initials: W
authors.lastname: Zhu
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Gong
authors.forename: Lili
authors.initials: L
authors.lastname: Gu
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.forename: Zhen
authors.initials: Z
authors.lastname: Guo
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Jieshou
authors.initials: J
authors.lastname: Li
mesh_terms: D002585:Cesarean Section / Q000009:adverse effects*; D002648:Child; D003093:Colitis, Ulcerative / Q000209:etiology*; D003424:Crohn Disease / Q000209:etiology*; D005260:Female; D006801:Humans; D016017:Odds Ratio; D011247:Pregnancy; D012307:Risk Factors
keywords: Crohn’s disease; cesarean delivery; meta-analysis; risk factor; ulcerative colitis