title: Outcomes of infants born at 22-27 weeks' gestation in Victoria according to outborn/inborn birth status.
abstract: OBJECTIVE
  To compare mortality and serious morbidity rates between outborn and inborn livebirths at 22-27 weeks' gestation.
  
  
  METHODS
  Population-based cohort study.
  
  
  METHODS
  Victoria, Australia.
  
  
  METHODS
  Livebirths at 22-27 weeks' gestation free of major malformations in 2010-2011.
  
  
  METHODS
  Outcome data for outborn (born outside a tertiary perinatal centre) infants compared with inborn (born in a tertiary perinatal centre) infants were analysed by logistic regression, adjusted for gestational age, birth weight and sex.
  
  
  METHODS
  Infant mortality and serious morbidity rates to hospital discharge.
  
  
  RESULTS
  541 livebirths free of major malformations were recorded. By 1 year, 49 (58%) outborns and 140 (31%) inborns died (adjusted OR (aOR) 2.78, 95% CI 1.52 to 5.09, p=0.001). In total, 445 infants were admitted to neonatal intensive care unit (NICU); 93 died by 1 year (14/49 outborns and 79/396 inborns), (aOR 1.75, 95% CI 0.87 to 3.55, p=0.12). There were no significant differences in rates of necrotising enterocolitis, intraventricular haemorrhage, retinopathy of prematurity, bronchopulmonary dysplasia (BPD) or the combined outcome of death or BPD in outborn infants compared with inborn infants. Outborns had an increased risk of cystic periventricular leukomalacia (cPVL) compared with inborns (12.2% vs 2.8%, respectively; aOR 5.34, 95% CI 1.84 to 15.54, p=0.002).
  
  
  CONCLUSIONS
  Mortality rates remained higher for outborn livebirths at 22-27 weeks' gestation compared with inborn peers in 2010-2011. Outborn infants admitted to NICU did not have substantially different rates of mortality or serious morbidity compared with inborns, with the exception of cPVL. Longer-term health consequences of outborn birth before 28 weeks' gestation need to be determined.
authors.affiliation: Murdoch Childrens Research Institute, Parkville, Victoria, Australia.|Department of Obstetrics and Gynecology, University of Melbourne, Royal Women's Hospital, Parkville, Victoria, Australia.|Paediatric Infant Perinatal Emergency Retrieval, Royal Children's Hospital, Parkville, Victoria, Australia.
authors.forename: Rosemarie Anne
authors.identifier: http://orcid.org/0000-0002-8127-2133
authors.initials: RA
authors.lastname: Boland
authors.affiliation: Department of Obstetrics and Gynecology, University of Melbourne, Royal Women's Hospital, Parkville, Victoria, Australia.|Department of Newborn Research, Royal Women's Hospital, Parkville, Victoria, Australia.
authors.forename: Peter Graham
authors.initials: PG
authors.lastname: Davis
authors.affiliation: Murdoch Childrens Research Institute, Parkville, Victoria, Australia.|Department of Obstetrics and Gynecology, University of Melbourne, Royal Women's Hospital, Parkville, Victoria, Australia.|Department of Newborn Research, Royal Women's Hospital, Parkville, Victoria, Australia.
authors.forename: Jennifer Anne
authors.initials: JA
authors.lastname: Dawson
authors.affiliation: Murdoch Childrens Research Institute, Parkville, Victoria, Australia.|Department of Obstetrics and Gynecology, University of Melbourne, Royal Women's Hospital, Parkville, Victoria, Australia.|Department of Newborn Research, Royal Women's Hospital, Parkville, Victoria, Australia.
authors.forename: Lex William
authors.initials: LW
authors.lastname: Doyle
mesh_terms: D001315:Australia / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007226:Infant Mortality; D007231:Infant, Newborn; D007234:Infant, Premature; D007235:Infant, Premature, Diseases / Q000453:epidemiology*; D007363:Intensive Care Units, Neonatal / Q000706:statistics & numerical data*; D008297:Male; D009017:Morbidity; D014739:Victoria / Q000453:epidemiology
keywords: Extremely preterm; Inborn; Morbidity; Mortality; Outborn