title: Small-for-gestational age and large-for-gestational age thresholds to predict infants at risk of adverse delivery and neonatal outcomes: are current charts adequate? An observational study from the Born in Bradford cohort.
abstract: OBJECTIVE
  Construct an ethnic-specific chart and compare the prediction of adverse outcomes using this chart with the clinically recommended UK-WHO and customised birth weight charts using cut-offs for small-for-gestational age (SGA: birth weight <10th centile) and large-for-gestational age (LGA: birth weight >90th centile).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Born in Bradford (BiB) study, UK.
  
  
  METHODS
  3980 White British and 4448 Pakistani infants with complete data for gestational age, birth weight, ethnicity, maternal height, weight and parity.
  
  
  METHODS
  Prevalence of SGA and LGA, using the three charts and indicators of diagnostic utility (sensitivity, specificity and area under the receiver operating characteristic (AUROC)) of these chart-specific cut-offs to predict delivery and neonatal outcomes and a composite outcome.
  
  
  RESULTS
  In White British and Pakistani infants, the prevalence of SGA and LGA differed depending on the chart used. Increased risk of SGA was observed when using the UK-WHO and customised charts as opposed to the ethnic-specific chart, while the opposite was apparent when classifying LGA infants. However, the predictive utility of all three charts to identify adverse clinical outcomes was poor, with only the prediction of shoulder dystocia achieving an AUROC>0.62 on all three charts.
  
  
  CONCLUSIONS
  Despite being recommended in national clinical guidelines, the UK-WHO and customised birth weight charts perform poorly at identifying infants at risk of adverse neonatal outcomes. Being small or large may increase the risk of an adverse outcome; however, size alone is not sensitive or specific enough with current detection to be useful. However, a significant amount of missing data for some of the outcomes may have limited the power needed to determine true associations.
authors.affiliation: Centre for Global Health and Human Development, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
authors.forename: T
authors.initials: T
authors.lastname: Norris
authors.affiliation: MRC Unit for Lifelong Health & Ageing, University College London, London, UK.
authors.forename: W
authors.initials: W
authors.lastname: Johnson
authors.affiliation: Bradford Institute for Health Research, Bradford Royal Infirmary, Bradford, UK.
authors.forename: D
authors.initials: D
authors.lastname: Farrar
authors.affiliation: Bradford Teaching Hospitals NHS Foundation Trust, Bradford Royal Infirmary, Bradford, UK.
authors.forename: D
authors.initials: D
authors.lastname: Tuffnell
authors.affiliation: Bradford Institute for Health Research, Bradford Royal Infirmary, Bradford, UK.
authors.forename: J
authors.initials: J
authors.lastname: Wright
authors.affiliation: Centre for Global Health and Human Development, School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
authors.forename: N
authors.initials: N
authors.lastname: Cameron
mesh_terms: D000328:Adult; D019540:Area Under Curve; D001724:Birth Weight; D036861:Delivery, Obstetric / Q000009:adverse effects*; D004420:Dystocia / Q000208:ethnology / Q000209:etiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D008297:Male; D008499:Medical Records / Q000592:standards; D007744:Obstetric Labor Complications / Q000208:ethnology / Q000209:etiology*; D010154:Pakistan / Q000208:ethnology; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000208:ethnology*; D011446:Prospective Studies; D012372:ROC Curve; D012307:Risk Factors; D006113:United Kingdom; D055815:Young Adult
keywords: EPIDEMIOLOGY; NEONATOLOGY; PERINATOLOGY