title: Predicting significant hyperbilirubinaemia using birth weight.
abstract: BACKGROUND
  A recent study proposed a risk factor scoring system for prediction of hyperbilirubinaemia that assigned increased risk to infants of higher birth weight.
  
  
  OBJECTIVE
  To investigate this novel finding in a large, retrospective cohort analysis.
  
  
  METHODS
  105 384 newborns (> or =2000 g and > or =36 weeks) were analysed, and the effect of higher birth weight on total serum bilirubin (TSB) > or =342 micromol/l was reported using logistic regression to control for gestational age, scalp injury diagnosis, maternal diabetes, method of delivery and other confounders.
  
  
  RESULTS
  The odds ratio for the effect of an additional 500 g of birth weight on TSB > or =342 micromol/l declined with increasing gestational age from 1.55 (95% CI 1.28 to 1.87) at 36 weeks to 1.30 (95% CI 1.12 to 1.50) at 37 weeks and 1.14 (95% CI 1.01 to 1.29) at 38 weeks. There was no association for infants > or =39 weeks.
  
  
  CONCLUSIONS
  Higher birth weight predicts TSB > or =342 micromol/l in 36-38 week infants, but not in infants > or =39 weeks. Further research should explore the causal mechanism for the association in less-mature infants.
authors.affiliation: Division of General Pediatrics, University of California, San Francisco, California, USA. FlahermanV@peds.ucsf.edu
authors.forename: V J
authors.initials: VJ
authors.lastname: Flaherman
authors.forename: A
authors.initials: A
authors.lastname: Ferrara
authors.forename: T B
authors.initials: TB
authors.lastname: Newman
mesh_terms: D001663:Bilirubin / Q000097:blood*; D001724:Birth Weight; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006932:Hyperbilirubinemia / Q000175:diagnosis* / Q000209:etiology; D007231:Infant, Newborn; D008297:Male; D016017:Odds Ratio; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors
chemical_list: D001663:Bilirubin