title: A comparison of the merits of using birth weight, or appropriateness of birth weight to gestational age, in the assessment of subsequent growth in twin children.
abstract: BACKGROUND
  Size at birth has an important relationship to subsequent growth. Many reports subgroup subjects according to birth weight or birth weight in relation to the duration of gestation, and it is not clear whether one of these methods is more relevant to subsequent growth or if in fact they are comparable.
  
  
  OBJECTIVE
  The present study compared the outcome of twins in terms of pre-pubertal weight and height when sub-grouped according to birth weight (BW), or the appropriateness of birth weight for the duration of gestation (BW-SDS).
  
  
  METHODS
  The birth weights of 1533 twins were graded into four subgroups according to BW or BW-SDS. The relationship of birth weight to subsequent weight and height standard deviation scores, obtained between the ages of 2 and 9 years, were compared on the basis of these two methods.
  
  
  RESULTS
  There was a marked difference in identity of the twins who fell into each of the four subgroups by the two methods. Despite this, no difference was found in the subsequent weight and height of the twins.
  
  
  CONCLUSIONS
  Analysis of data relating BW-SDS to subsequent growth shows no significant difference to those groups using BW alone.
authors.affiliation: Department of Paediatrics and Child Health, University of Leeds, UK.
authors.forename: M
authors.initials: M
authors.lastname: Green
authors.forename: J M H
authors.initials: JM
authors.lastname: Buckler
mesh_terms: D000883:Anthropology / Q000379:methods; D001724:Birth Weight; D001827:Body Height; D001835:Body Weight; D002648:Child; D002657:Child Development / Q000502:physiology; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D014427:Twins / Q000502:physiology