title: Perinatal morbidity associated with late preterm deliveries compared with deliveries between 37 and 40 weeks of gestation.
abstract: OBJECTIVE
  To estimate the risk of short-term complications in neonates born between 34 and 36 weeks of gestation.
  
  
  METHODS
  This is a retrospective cohort study.
  
  
  METHODS
  Deliveries in 2005 in the USA.
  
  
  METHODS
  Singleton live births between 34 and 40 weeks of gestation.
  
  
  METHODS
  Gestational age was subgrouped into 34, 35, 36 and 37-40 completed weeks of gestation. Statistical comparisons were performed using chi-square test and multivariable logistic regression models, with 37-40 weeks of gestation designated as referent.
  
  
  METHODS
  Perinatal morbidities, including 5-minute Apgar scores, hyaline membrane disease, neonatal sepsis/antibiotics use, and admission to the intensive care unit.
  
  
  RESULTS
  In all, 175,112 neonates were born between 34 and 36 weeks in 2005. Compared with neonates born between 37 and 40 weeks, neonates born at 34 weeks had higher odds of 5-minute Apgar <7 (adjusted odds ratio [aOR] 5.51, 95% CI 5.16-5.88), hyaline membrane disease (aOR 10.2, 95% CI 9.44-10.9), mechanical ventilation use >6 hours (aOR 9.78, 95% CI 8.99-10.6) and antibiotic use (aOR 9.00, 95% CI 8.43-9.60). Neonates born at 35 weeks were similarly at risk of morbidity, with higher odds of 5-minute Apgar <7 (aOR 3.42, 95% CI 3.23-3.63), surfactant use (aOR 3.74, 95% CI 3.21-4.22), ventilation use >6 hours (aOR 5.53, 95% CI 5.11-5.99) and neonatal intensive-care unit admission (aOR 11.3, 95% CI 11.0-11.7). Neonates born at 36 weeks remain at higher risk of morbidity compared with deliveries at 37-40 weeks of gestation.
  
  
  CONCLUSIONS
  Although the risk of undesirable neonatal outcomes decreases with increasing gestational age, the risk of neonatal complications in late preterm births remains higher compared with infants delivered at 37-40 weeks of gestation.
authors: Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, 94143-0132, USA. yvecheng@hotmail.com
authors: Y W
authors: YW
authors: Cheng
authors: A J
authors: AJ
authors: Kaimal
authors: T A
authors: TA
authors: Bruckner
authors: D R
authors: DR
authors: Halloran
authors: D R
authors: DR
authors: Hallaron
authors: A B
authors: AB
authors: Caughey
mesh_terms: D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001034:Apgar Score; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D006819:Hyaline Membrane Disease / Q000453:epidemiology; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data; D016015:Logistic Models; D016017:Odds Ratio; D010343:Patient Admission / Q000706:statistics & numerical data; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D012121:Respiration, Artificial / Q000706:statistics & numerical data; D012189:Retrospective Studies; D018805:Sepsis / Q000188:drug therapy / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents