title: Customised birthweight standards accurately predict perinatal morbidity.
abstract: OBJECTIVE
  Fetal growth restriction is associated with adverse perinatal outcome but is often not recognised antenatally, and low birthweight centiles based on population norms are used as a proxy instead. This study compared the association between neonatal morbidity and fetal growth status at birth as determined by customised birthweight centiles and currently used centiles based on population standards.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Referral hospital, Barcelona, Spain.
  
  
  METHODS
  A cohort of 13 661 non-malformed singleton deliveries.
  
  
  METHODS
  Both population-based and customised standards for birth weight were applied to the study cohort. Customised weight centiles were calculated by adjusting for maternal height, booking weight, parity, ethnic origin, gestational age at delivery and fetal sex.
  
  
  METHODS
  Newborn morbidity and perinatal death.
  
  
  RESULTS
  The association between smallness for gestational age (SGA) and perinatal morbidity was stronger when birthweight limits were customised, and resulted in an additional 4.1% (n=565) neonates being classified as SGA. Compared with non-SGA neonates, this newly identified group had an increased risk of perinatal mortality (OR 3.2; 95% CI 1.6 to 6.2), neurological morbidity (OR 3.2; 95% CI 1.7 to 6.1) and non-neurological morbidity (OR 8; 95% CI 4.8 to 13.6).
  
  
  CONCLUSIONS
  Customised standards improve the prediction of adverse neonatal outcome. The association between SGA and adverse outcome is independent of the gestational age at delivery.
authors.affiliation: Perinatal Institute, Crystal Court, Aston Cross, Birmingham, UK. Francesc.Figueras@perinatal.nhs.uk
authors.forename: Francesc
authors.initials: F
authors.lastname: Figueras
authors.forename: Josep
authors.initials: J
authors.lastname: Figueras
authors.forename: Eva
authors.initials: E
authors.lastname: Meler
authors.forename: Elisenda
authors.initials: E
authors.lastname: Eixarch
authors.forename: Oriol
authors.initials: O
authors.lastname: Coll
authors.forename: Eduard
authors.initials: E
authors.lastname: Gratacos
authors.forename: Jason
authors.initials: J
authors.lastname: Gardosi
authors.forename: Xavier
authors.initials: X
authors.lastname: Carbonell
mesh_terms: D001724:Birth Weight; D005260:Female; D005317:Fetal Growth Retardation / Q000453:epidemiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000196:embryology* / Q000453:epidemiology; D007236:Infant, Small for Gestational Age; D008297:Male; D011247:Pregnancy; D011256:Pregnancy Outcome; D011379:Prognosis; D012016:Reference Values; D012189:Retrospective Studies; D013030:Spain / Q000453:epidemiology