title: Customized large-for-gestational-age birthweight at term and the association with adverse perinatal outcomes.
abstract: OBJECTIVE
  Using a cohort of 110,447 singleton, term pregnancies, we aimed to validate the previously proposed customized standard of large-for-gestational-age (LGA) birthweight, derive an additional customized LGA model excluding maternal weight, and evaluate the association between differing definitions of customized LGA and perinatal morbidities.
  
  
  METHODS
  Three customized LGA classifications, in addition to a population-based 90th percentile, were made according to the principals described by Gardosi: (1) customized LGA using Gardosi's previously published coefficients (LGA-Gardosi), (2) customized LGA using coefficients derived by a similar method but from our larger cohort, and (3) derived without customization for maternal weight. Associations between the LGA classifications and various perinatal morbidity outcomes were evaluated.
  
  
  RESULTS
  Coefficients derived here for physiologic and pathologic effects on birthweight were similar to those previously reported by Gardosi. Customized LGA (any method) generally identified more births to younger, nonwhite, nulliparous mothers with female neonates of lower birthweight compared with population-based LGA. Rates of maternal and neonatal morbidity were greatest in births classified by both population-based LGA and customized LGA (any method). However, the model that excluded customization for maternal weight, revealed a greater proportion of women previously unidentified by population-based LGA who were more frequently black (40% vs 25%) and obese (30% vs 5.1%), along with greater rates of shoulder dystocia, neonatal intensive care unit admission and neonatal respiratory complications, than with LGA-Gardosi.
  
  
  CONCLUSIONS
  The use of customized methods of defining LGA was not decisively superior compared with population-based LGA, but custom LGA may be improved by modification of the parameters included in customization.
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Lindsey A
authors.initials: LA
authors.lastname: Sjaarda
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Paul S
authors.initials: PS
authors.lastname: Albert
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Sunni L
authors.initials: SL
authors.lastname: Mumford
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Stefanie N
authors.initials: SN
authors.lastname: Hinkle
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD.
authors.forename: Pauline
authors.initials: P
authors.lastname: Mendola
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD. Electronic address: laughonsk@mail.nih.gov.
authors.forename: S Katherine
authors.initials: SK
authors.lastname: Laughon
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D005320:Fetal Macrosomia / Q000150:complications / Q000175:diagnosis*; D005865:Gestational Age; D006801:Humans; D007226:Infant Mortality; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000175:diagnosis / Q000209:etiology*; D009017:Morbidity; D011247:Pregnancy; D011248:Pregnancy Complications; D011256:Pregnancy Outcome; D012189:Retrospective Studies; D055815:Young Adult
keywords: customized birthweight; delivery complications; large for gestational age; macrosomia; neonatal morbidity; neonatal mortality
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