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Birth prevalence of anorectal malformations in England and 5-year survival: a national birth cohort study
  1. Kathryn Ford1,2,
  2. Maria Peppa2,
  3. Ania Zylbersztejn2,
  4. Joe I Curry1,
  5. Ruth Gilbert2
  1. 1 Department of Specialist Neonatal and Paediatric Surgery, Great Ormond Street Hospital for Children, London, UK
  2. 2 Population, Policy and Practice Department, University College London Institute of Child Health, London, UK
  1. Correspondence to Dr Kathryn Ford, Department of Specialist Neonatal and Paediatric Surgery, Great Ormond Street Hospital for Children, London WC1N 3JH, UK; kathryneford{at}


Objective To determine the birth prevalence, maternal risk factors and 5-year survival for isolated and complex anorectal malformations.

Design National birth cohort using hospital admission data and death records.

Setting All National Health Service England hospitals.

Patients Live-born singletons delivered from 2002 through 2018, with evidence in the first year of life of a diagnosis of an anorectal malformation and repair during a hospital admission, or anorectal malformation recorded on the death certificate. Cases were further classified as isolated or complex depending on the presence of additional anomalies.

Main outcome measures Birth prevalence of anorectal malformations per 10 000 live births, risk ratios for isolated and complex anorectal malformation by maternal, infant and birth characteristics, and 5-year survival.

Results We identified 3325 infants with anorectal malformations among 9 474 147 live-born singletons; 61.7% (n=2050) of cases were complex. Birth prevalence was 3.5 per 10 000 live births (95% CI 3.4 to 3.6). Complex anorectal malformations were associated with maternal age extremes after accounting for other sociodemographic factors. Compared with maternal ages 25–34 years, the risk of complex anorectal malformations was 31% higher for ≥35 years (95% CI 17 to 48) and 13% higher for ≤24 years (95% CI 0 to 27). Among 2376 anorectal malformation cases (n=1450 complex) born from 2002 through 2014, 5-year survival was lower for complex (86.9%; 95% CI 85.1% to 88.5%) than isolated anorectal malformations (98.2%; 95% CI 97.1% to 98.9%). Preterm infants with complex anorectal malformations had the lowest survival (73.4%; 95% CI 68.1% to 78.0%).

Conclusions Differences in maternal risk factors for isolated and complex anorectal malformations may reflect different underlying mechanisms for occurrence. Five-year survival is high but lowest for preterm children with complex anorectal malformations.

  • Child Health
  • Epidemiology
  • Paediatrics
  • Mortality

Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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Data availability statement

All data relevant to the study are included in the article or uploaded as supplementary information.

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  • Contributors All authors contributed to the design of the study. KF and MP carried out analyses. KF wrote the first draft of the manuscript. All authors were involved in the interpretation of the data and made critical revisions to subsequent drafts. All authors have seen and approved the final version. KF and MP had full access to all of the data in the study and take responsibility for the integrity of the data and accuracy of the analyses. RG is guarantor for the study.

  • Funding This work was supported by the British Association of Paediatric Surgeons (KF), the Royal College of Surgeons of England (KF), the National Institute for Health Research (NIHR) Children and Families Policy Research Unit (RG and AZ) and the NIHR Great Ormond Street Biomedical Research Centre (MP).

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.