title: Trends in Morbidity and Mortality of Extremely Preterm Multiple Gestation Newborns.
abstract: OBJECTIVE
  To examine the risk of mortality and major morbidities in extremely preterm multiple gestation infants compared with singletons over time.
  
  
  METHODS
  This is a retrospective study of 15,402 infants born ≤27 weeks' gestation, admitted to NICUs in the Australian and New Zealand Neonatal Network from 1995 to 2009. Mortality and major morbidities were compared between singletons and multiples across three 5-year epochs.
  
  
  RESULTS
  Extreme preterm multiples were more likely to have lower birth weight; higher maternal age; and higher rates of assisted conception, antenatal steroid use, and cesarean delivery compared with singletons. The mortality rate was significantly higher in multiples compared with singletons even as there was a trend of decreasing gestational-age stratified mortality in multiples over the time period investigated. The rates of major morbidities or composite adverse outcomes were not different between multiples and singletons across all epochs. The adjusted odds ratio (AOR) for mortality in multiples was significantly higher in multiples compared with singletons (AOR 1.20, 95% confidence interval [CI] 1.08-1.34). There were no differences in the adjusted odds for poor outcomes in multiples compared with singletons in the most recent epoch: mortality (AOR 1.00, 95% CI 0.84-1.19), major morbidity (0.95, 95% CI 0.81-1.10), and composite adverse outcome (0.96, 95% CI 0.83-1.11).
  
  
  CONCLUSIONS
  Over the 15-year period, the odds for mortality in extremely preterm NICU infants of multiple gestation was significantly higher compared with singletons. The adjusted odds of poor outcomes in multiples were not significantly different from that of singletons in the most recent epoch.
authors.affiliation: Department of Newborn Care, Royal Hospital for Women, Randwick, Australia; Department of Neonatology, KK Women's and Children's Hospital, Singapore;
authors.forename: Kee Thai
authors.initials: KT
authors.lastname: Yeo
authors.affiliation: School of Women's and Child's Health, University of New South Wales, Sydney, Australia; and.
authors.forename: Qin Ying
authors.initials: QY
authors.lastname: Lee
authors.affiliation: Department of Newborn Care, Royal Hospital for Women, Randwick, Australia;Department of Neonatology, KK Women's and Children's Hospital, Singapore;School of Women's and Child's Health, University of New South Wales, Sydney, Australia; andFaculty of Health, University of Technology, Sydney, Australia.
authors.forename: Wei Shern
authors.initials: WS
authors.lastname: Quek
authors.affiliation: Faculty of Health, University of Technology, Sydney, Australia.
authors.forename: Yueping Alex
authors.initials: YA
authors.lastname: Wang
authors.affiliation: Department of Newborn Care, Royal Hospital for Women, Randwick, Australia; School of Women's and Child's Health, University of New South Wales, Sydney, Australia; and.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Bolisetty
authors.affiliation: Department of Newborn Care, Royal Hospital for Women, Randwick, Australia; School of Women's and Child's Health, University of New South Wales, Sydney, Australia; and kei.lui@sesiahs.health.nsw.gov.au.
authors.forename: Kei
authors.initials: K
authors.lastname: Lui
mesh_terms: D005260:Female; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D008297:Male; D009017:Morbidity / Q000639:trends; D011247:Pregnancy; D011272:Pregnancy, Multiple; D012189:Retrospective Studies; D018570:Risk Assessment