Document resource
Objectives Autism spectrum disorder (ASD) is a neurodevelopmental condition characterised by impairments in social communication behaviours and skills. Functional gastrointestinal (GI) disorders (FGIDs) as defined in Rome criteria are common in children with ASD. We aimed to systematically review the literature on the prevalence of FGID in children with ASD.Methods Systematic search of Embase, MEDLINE, Global Health and American Psychological Association PsycINFO databases following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for FGID and their subtypes and ASD.Results 3431 articles were identified and 527 were duplicates. 2862 were excluded by title, abstract and full-text screen. 44 articles were included, 2 added from reference search. FGID data were collected from 17 924 children with ASD from 18 countries. Overall prevalence was 22.7%–93.2%. Constipation (29.8%) and functional abdominal pain (14.5%) were the most prevalent conditions, with a wide reported range. Other types of FGIDs are less frequently reported.Conclusions FGIDs are prevalent in children with ASD, with constipation and abdominal pain being the predominant types. There is wide heterogeneity in the reported prevalence, with some studies reporting near universal prevalence.