title: Hypertensive disease of pregnancy is associated with decreased risk for respiratory distress syndrome in moderate preterm neonates.
abstract: OBJECTIVE
  To examine the effect of hypertensive disease of pregnancy (HDP) on the development of respiratory distress syndrome (RDS) in preterm neonates.
  
  
  METHODS
  A retrospective cohort study.
  
  
  METHODS
  All neonatal intensive care units in New South Wales and the Australian Capital Territory.
  
  
  METHODS
  A total of 18,845 preterm neonates aged between 24 and 36 weeks gestation admitted to the units from 1998 to 2006 were included for study purpose. Exclusion criteria were multiple pregnancies, chorioamnionitis, antepartum hemorrhage and neonates who developed respiratory diagnoses other than RDS.
  
  
  METHODS
  Effect of HDP on the development of RDS was measured.
  
  
  RESULTS
  A total of 1093 neonates from hypertensive and 2274 from normotensive pregnancies with complete datasets were included. The association between HDP and the development of RDS was modified by gestational age (HDP-by-gestational age interaction p value <0.0001). Therefore the cohort was divided into extreme (24-28 weeks gestation, n = 752), severe (29-32 weeks gestation, n = 1448) and moderate (33-36 weeks gestation, n = 1167) preterm groups. HDP was associated with a decreased risk of RDS in the moderate preterm group (OR: 0.68; 95% CI: 0.48-0.98, p = 0.04) and a non-significant change in risk for the severe preterm group. Almost all neonates in the extreme preterm group experienced RDS.
  
  
  CONCLUSIONS
  HDP is associated with a lower risk of developing RDS in moderate preterm neonates. This could have clinical implications in terms of risk stratification for this group of neonates.
authors.affiliation: Discipline of Paediatrics, Sydney Medical School - Nepean, Nepean Hospital, The University of Sydney, Penrith, Australia. liua@wahs.nsw.gov.au
authors.forename: Anthony
authors.initials: A
authors.lastname: Liu
authors.forename: Eva
authors.initials: E
authors.lastname: Carlsson
authors.forename: Sofia
authors.initials: S
authors.lastname: Nilsson
authors.forename: Julee
authors.initials: J
authors.lastname: Oei
authors.forename: Barbara
authors.initials: B
authors.lastname: Bajuk
authors.forename: Michael
authors.initials: M
authors.lastname: Peek
authors.forename: Andrew
authors.initials: A
authors.lastname: Martin
authors.forename: Ralph
authors.initials: R
authors.lastname: Nanan
mesh_terms: D000328:Adult; D020958:Australian Capital Territory / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D006801:Humans; D046110:Hypertension, Pregnancy-Induced / Q000453:epidemiology*; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D016015:Logistic Models; D009517:New South Wales / Q000453:epidemiology; D011247:Pregnancy; D012127:Respiratory Distress Syndrome, Newborn / Q000453:epidemiology*; D012189:Retrospective Studies; D055815:Young Adult