title: Persistence of underweight status among late preterm infants.
abstract: OBJECTIVE
  To determine the association of late preterm gestation (34-36 weeks' gestation) with underweight status in infancy.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Thirty-one primary care sites within a hospital-owned network, from January 1, 2007, through June 30, 2009.
  
  
  METHODS
  Seven thousand eight hundred sixty-six infants with gestational ages ranging from 34 to 42 weeks, followed up through the first 18 months of life. Analytic sample consisted of 7624 infants examined at 6 months of age; 7132, at 1 year; and 6957, at 18 months.
  
  
  METHODS
  Late preterm (34-36 weeks), early term (37-38 weeks), or full-term (39-42 weeks) gestation.
  
  
  METHODS
  Weight-for-age z score of 2 or less at 6, 12, and 18 months.
  
  
  RESULTS
  Compared with full-term gestation, late preterm gestation was associated with increased adjusted odds ratios (AORs) of weight-for-age z score of 2 or less at 6 months (AOR, 3.48 [95% CI, 2.17-5.72]) and 12 months (2.22 [1.07-4.61]). At 18 months, this association was not significant (AOR, 1.62 [95% CI, 0.69-3.84]). After exclusion of infants who were small for their gestational age, late prematurity was associated with underweight status when defined as a decline from birth weight of more than the 10th percentile to a weight-for-age z score of 2 or less at 6 months (AOR, 3.35 [95% CI, 1.76-6.38]) and 12 months (2.72 [1.02-7.27]) but not 18 months (1.88 [0.64-5.55]).
  
  
  CONCLUSIONS
  There is an association between late prematurity and underweight status in the first year of life. Further research is needed to determine the effect of this growth pattern on developmental outcomes and to optimize nutritional management.
authors.affiliation: Division of Neonatology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA. neera.goyal@cchmc.org
authors.forename: Neera K
authors.initials: NK
authors.lastname: Goyal
authors.forename: Alexander G
authors.initials: AG
authors.lastname: Fiks
authors.forename: Scott A
authors.initials: SA
authors.lastname: Lorch
mesh_terms: D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000254:growth & development*; D016015:Logistic Models; D008297:Male; D015999:Multivariate Analysis; D016017:Odds Ratio; D011247:Pregnancy; D047928:Premature Birth; D012189:Retrospective Studies; D013851:Thinness / Q000209:etiology*