title: Birthweight by gestational age in preterm babies according to a Gaussian mixture model.
abstract: OBJECTIVE
  To provide a statistically sound criterion for identifying implausibly large birthweights for gestational age.
  
  
  METHODS
  Review of ISTAT 1990-1994 national newborn records.
  
  
  METHODS
  Italy
  
  
  METHODS
  Forty-two thousand and twenty-nine single first and second liveborn preterm babies.
  
  
  METHODS
  Two-component Gaussian mixture models are used to describe the birthweight distributions stratified by gestational age. Implausibly large babies are identified through model-based probabilistic clustering.
  
  
  METHODS
  Gestational age misclassification and weight-for-gestational age centile curves
  
  
  RESULTS
  Gestational age appears under-estimated by about six weeks in 12.3% of the cases. Large babies are equally present in males and females, but are more frequent in second-borns than in first-borns, even when parity-specific models are fitted.
  
  
  CONCLUSIONS
  The approach allows for a quantification of the gestational age under-estimate error and for data correction through model-based clustering. Correct birthweight distributions and growth curves are also provided.
authors.affiliation: Institute of Applied Mathematics and Computer Technologies, CNR, Pavia, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Tentoni
authors.forename: Paola
authors.initials: P
authors.lastname: Astolfi
authors.forename: Antonio
authors.initials: A
authors.lastname: De Pasquale
authors.forename: Laura A
authors.initials: LA
authors.lastname: Zonta
mesh_terms: D001724:Birth Weight; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D008954:Models, Biological; D015233:Models, Statistical; D016011:Normal Distribution; D011336:Probability