title: Neonatal Morbidity and 1-Year Survival of Extremely Preterm Infants.
abstract: OBJECTIVE
  To determine 1-year survival and major neonatal morbidities (intracranial hemorrhage grade >2, cystic periventricular leukomalacia, retinopathy of prematurity grade >2, necrotizing enterocolitis, severe bronchopulmonary dysplasia) among extremely preterm infants in Norway in 2013-2014, and to compare the results to the first Norwegian Extreme Prematurity Study 1999-2000 and similar contemporary European population-based studies.
  
  
  METHODS
  Population-based study of all infants born at 22 through 26 weeks' gestation in Norway in 2013-2014. Prospectively collected data were obtained by linking data in the Norwegian Neonatal Network to the Medical Birth Registry of Norway.
  
  
  RESULTS
  Of 420 infants (incidence 3.5 per 1000 births), 145 were stillborn (34.5%), 275 were live-born (82.3% of the 334 fetuses alive at admission for obstetrical care), and 251 (91.3% of live-born infants) were admitted to a neonatal unit. The survival among live-born infants was 18% at 22 weeks, 29% at 23 weeks, 56% at 24 weeks, 84% at 25 weeks and 90% at 26 weeks (for each week increment in gestational age: odds ratio 3.3; 95% confidence interval, 2.4-4.4). Among infants surviving to 1 year of age, major neonatal morbidity was diagnosed in 55%. Decreasing gestational age was moderately associated with rates of major morbidity (odds ratio 1.6; 95% confidence interval, 1.2-2.2).
  
  
  CONCLUSIONS
  Compared to the previous 1999-2000 cohort, the rate of stillbirth before admission to an obstetrical unit increased, whereas the survival rate among live born infants was similar in our 2013-2014 cohort. Neonatal morbidity rates remain high among extremely preterm infants.
authors.affiliation: Division of Paediatric and Adolescent Medicine, Neonatal Department, and hstensvo@ous-hf.no.|Norwegian Neonatal Network, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Norway.
authors.forename: Hans Jorgen
authors.initials: HJ
authors.lastname: Stensvold
authors.affiliation: Division of Child and Adolescent Health. University Hospital of North Norway, Tromso, Norway.|Paediatric Research Group, Department of Health Sciences, University of Tromso, Norway.
authors.forename: Claus
authors.initials: C
authors.lastname: Klingenberg
authors.affiliation: Department of Pediatrics, St Olav Hospital, Trondheim, Norway.|Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Ragnhild
authors.initials: R
authors.lastname: Stoen
authors.affiliation: Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.|Department of Global Public Health and Primary Care, University of Bergen, Norway.|Medical Birth Registry of Norway, Norwegian Institute of Public Health, Oslo, Norway.
authors.forename: Dag
authors.initials: D
authors.lastname: Moster
authors.affiliation: Division of Paediatric and Adolescent Medicine, Neonatal Department, and.
authors.forename: Kristin
authors.initials: K
authors.lastname: Braekke
authors.affiliation: Department of Pediatrics, Haukeland University Hospital, Bergen, Norway.
authors.forename: Hans Jorgen
authors.initials: HJ
authors.lastname: Guthe
authors.affiliation: Department of Pediatrics, Sorlandet Hospital Trust, Kristiansand, Norway.
authors.forename: Henriette
authors.initials: H
authors.lastname: Astrup
authors.affiliation: Children's Department, Stavanger University Hospital, Stavanger, Norway; and.
authors.forename: Siren
authors.initials: S
authors.lastname: Rettedal
authors.affiliation: Department of Pediatric and Adolescent Medicine, Akershus University Hospital, Lorenskog, Norway.
authors.forename: Morten
authors.initials: M
authors.lastname: Gronn
authors.affiliation: Division of Paediatric and Adolescent Medicine, Neonatal Department, and.|Norwegian Neonatal Network, Oslo University Hospital, Oslo, Norway.|Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Norway.
authors.forename: Arild E
authors.initials: AE
authors.lastname: Ronnestad
mesh_terms: D001997:Bronchopulmonary Dysplasia / Q000453:epidemiology; D002543:Cerebral Hemorrhage / Q000453:epidemiology; D020345:Enterocolitis, Necrotizing / Q000453:epidemiology; D005260:Female; D005865:Gestational Age; D017052:Hospital Mortality; D006801:Humans; D062071:Infant, Extremely Premature; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000453:epidemiology; D007363:Intensive Care Units, Neonatal; D007969:Leukomalacia, Periventricular / Q000453:epidemiology; D008297:Male; D009664:Norway / Q000453:epidemiology; D010343:Patient Admission / Q000706:statistics & numerical data; D012042:Registries; D012178:Retinopathy of Prematurity / Q000453:epidemiology; D018805:Sepsis / Q000453:epidemiology; D050497:Stillbirth / Q000453:epidemiology; D015996:Survival Rate; D028761:Withholding Treatment / Q000706:statistics & numerical data