title: A customized standard of large size for gestational age to predict intrapartum morbidity.
abstract: OBJECTIVE
  The purpose of this study was to determine whether a customized standard of large-for-gestational age (LGA) identifies pregnancies with increased perinatal risk.
  
  
  METHODS
  We evaluated 7510 estimates of fetal weight to generate a fetal growth curve. Next, we analyzed the gestational age at delivery, physiologic and pathological variables from 5072 pregnancies to predict birthweight, and calculated a customized ideal birthweight and cutoff for LGA. In a separate analysis of 32,271 pregnancies, rates of macrosomia-related adverse outcomes were compared in pregnancies that had been identified as LGA by a customized standard (LGA(cust)) and those pregnancies that had been identified as LGA or macrosomic by conventional standards.
  
  
  RESULTS
  LGA(cust) pregnancies carried increased risk of shoulder dystocia, third- or fourth-degree laceration, and cephalopelvic disproportion. LGA(cust) pregnancies that did not meet conventional criteria for LGA/macrosomia were at increased risk of all measured outcomes.
  
  
  CONCLUSIONS
  A customized standard of LGA identifies a previously unrecognized population that is at increased risk of perinatal morbidity.
authors.affiliation: Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh School of Medicine, PA, USA. larkinjc@mail.magee.edu
authors.forename: Jacob C
authors.initials: JC
authors.lastname: Larkin
authors.forename: Paul D
authors.initials: PD
authors.lastname: Speer
authors.forename: Hyagriv N
authors.initials: HN
authors.lastname: Simhan
mesh_terms: D000328:Adult; D001724:Birth Weight; D005260:Female; D047109:Fetal Development; D005320:Fetal Macrosomia / Q000175:diagnosis*; D020567:Fetal Weight; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D007744:Obstetric Labor Complications / Q000453:epidemiology*; D011247:Pregnancy; D012016:Reference Values; D012189:Retrospective Studies; D012307:Risk Factors