Background Cesarean section (CS) rates continue rising worldwide, raising concerns about long-term offspring health consequences, including inflammatory bowel disease (IBD). This systematic review and meta-analysis evaluate the association between CS and risk of IBD, Crohn's disease (CD), and ulcerative colitis (UC). Methods PubMed, Scopus, CENTRAL, and Web of Science were searched through June 2025. Eligible studies included observational cohorts and case-control studies reporting CS vs. vaginal delivery (VD) and IBD outcomes. Data extraction and risk of bias assessment were performed independently. Pooled relative risks (RRs), hazard ratios (HRs), and odds ratios (ORs) were calculated using fixed or random-effects models. Subgroup analyses and publication bias assessment were conducted. Results Twenty-two studies comprising over 13 million births were included. Unadjusted analyses showed no association between CS and IBD (RR: 0.98, 95% CI: 0.88–1.08), CD (RR: 0.99, 95% CI: 0.88–1.12), however, an inverse association was observed for UC (RR: 0.82, 95% CI: 0.72–0.95). Regional variation was observed, with CS associated with reduced IBD risk in Denmark, Switzerland, and Norway, but increased risk in Germany and Australia. Adjusted analyses consistently demonstrated no association: IBD (HR: 1.14, 95% CI: 0.99–1.30; OR: 0.91, 95% CI: 0.65–1.25), CD (HR: 1.07, 95% CI: 0.90–1.28; OR: 1.11, 95% CI: 0.98–1.26), and UC (HR: 0.96, 95% CI: 0.87–1.05; OR: 1.05, 95% CI: 0.86–1.27). No publication bias was detected. Conclusion Across over 13 million births, delivery mode was not associated with IBD, CD, or UC risk. Despite biologically plausible mechanisms linking CS to altered microbiome patterns, epidemiological evidence does not support CS as an independent IBD risk factor. These findings provide reassurance for clinical counseling regarding CS and long-term IBD risk. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420251237413 , PROSPERO CRD420251237413.
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