title: Mode of delivery and risk of inflammatory bowel disease in the offspring: systematic review and meta-analysis of observational studies.
abstract: BACKGROUND
  The incidence of inflammatory bowel disease (IBD) is increasing worldwide; however, pathogenesis is not fully understood. The global cesarean section (CS) rate is also rising, and evidence suggests that mode of delivery may influence colonization of the offspring gut microbiota, predisposing offspring to IBD. This study aimed to investigate the relationship between mode of delivery and risk of IBD.
  
  
  METHODS
  The electronic databases, Embase, CINAHL, and Medline (1948 to present) were searched, reference lists were checked, and no restrictions were assigned. Full texts of potentially relevant articles were evaluated, and included articles were assessed for quality. Raw data were used to calculate unadjusted odds ratios reflecting the risk of developing IBD in those delivered by cesarean. A meta-analysis was performed using RevMan 5 software to obtain a pooled measure of effect. Sensitivity analyses were performed to identify results according to specific study designs.
  
  
  RESULTS
  Seven eligible studies were included; 4 were retrospective cohort design and 3 were case-control studies. The total number of children born by CS in the meta-analysis was 1354, and 11,355 were delivered vaginally. The proportion of IBD in the CS group was 0.249% compared with 0.322% in the vaginal delivery group. The pooled odds ratio of developing IBD when delivered by CS was 1.00 (95% confidence interval, 0.75-1.33).
  
  
  CONCLUSIONS
  This analysis observed no significant difference in risk of IBD in offspring delivered by CS compared with those born vaginally.
authors.affiliation: *University of Aberdeen Medical School, Aberdeen, United Kingdom; and Departments of †Obstetrics and Gynaecology, and ‡Epidemiology, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Alanna
authors.initials: A
authors.lastname: Bruce
authors.forename: Mairead
authors.initials: M
authors.lastname: Black
authors.forename: Sohinee
authors.initials: S
authors.lastname: Bhattacharya
mesh_terms: D002585:Cesarean Section / Q000009:adverse effects* / Q000379:methods; D036861:Delivery, Obstetric / Q000009:adverse effects / Q000379:methods; D005260:Female; D006801:Humans; D015994:Incidence; D007231:Infant, Newborn; D015212:Inflammatory Bowel Diseases / Q000453:epidemiology / Q000209:etiology*; D008297:Male; D009321:Natural Childbirth; D011247:Pregnancy; D011379:Prognosis; D018570:Risk Assessment