{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,30]],"date-time":"2026-10-30T23:11:15Z","timestamp":1793401875800,"version":"4.5.0"},"reference-count":39,"publisher":"American Medical Association (AMA)","issue":"12","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JAMA"],"published-print":{"date-parts":[[2019,3,26]]},"abstract":"\n Importance<\/jats:title>\n Since 2004-2007, national guidelines and recommendations have been developed for the management of extremely preterm births in Sweden. If and how more uniform management has affected infant survival is unknown.<\/jats:p>\n <\/jats:sec>\n \n Objective<\/jats:title>\n To compare survival of extremely preterm infants born during 2004-2007 with survival of infants born during 2014-2016.<\/jats:p>\n <\/jats:sec>\n \n Design, Setting and Participants<\/jats:title>\n All births at 22-26 weeks\u2019 gestational age (n\u2009=\u20092205) between April 1, 2004, and March 31, 2007, and between January 1, 2014, and December 31, 2016, in Sweden were studied. Prospective data collection was used during 2004-2007. Data were obtained from the Swedish pregnancy, medical birth, and neonatal quality registries during 2014-2016.<\/jats:p>\n <\/jats:sec>\n \n Exposures<\/jats:title>\n Delivery at 22-26 weeks\u2019 gestational age.<\/jats:p>\n <\/jats:sec>\n \n Main Outcomes and Measures<\/jats:title>\n The primary outcome was infant survival to the age of 1 year. The secondary outcome was 1-year survival among live-born infants who did not have any major neonatal morbidity (specifically, without intraventricular hemorrhage grade 3-4, cystic periventricular leukomalacia, necrotizing enterocolitis, retinopathy of prematurity stage 3-5, or severe bronchopulmonary dysplasia).<\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n During 2004-2007, 1009 births (3.3\/1000 of all births) occurred at 22-26 weeks\u2019 gestational age compared with 1196 births (3.4\/1000 of all births) during 2014-2016 (\n P<\/jats:italic>\n \u2009=\u2009.61). One-year survival among live-born infants at 22-26 weeks\u2019 gestational age was significantly lower during 2004-2007 (497 of 705 infants [70%]) than during 2014-2016 (711 of 923 infants [77%]) (difference, \u22127% [95% CI, \u221211% to \u22122.2%],\n P<\/jats:italic>\n \u2009=\u2009.003). One-year survival among live-born infants at 22-26 weeks\u2019 gestational age and without any major neonatal morbidity was significantly lower during 2004-2007 (226 of 705 infants [32%]) than during 2014-2016 (355 of 923 infants [38%]) (difference, \u22126% [95% CI, \u221211% to \u22121.7%],\n P<\/jats:italic>\n \u2009=\u2009.008).\n <\/jats:p>\n <\/jats:sec>\n \n Conclusions and Relevance<\/jats:title>\n Among live births at 22-26 weeks\u2019 gestational age in Sweden, 1-year survival improved between 2004-2007 and 2014-2016.<\/jats:p>\n <\/jats:sec>","DOI":"10.1001\/jama.2019.2021","type":"journal-article","created":{"date-parts":[[2019,3,26]],"date-time":"2019-03-26T11:31:46Z","timestamp":1553599906000},"page":"1188","source":"Crossref","is-referenced-by-count":291,"title":["Association Between Year of Birth and 1-Year Survival Among Extremely Preterm Infants in Sweden During 2004-2007 and 2014-2016"],"prefix":"10.1001","volume":"321","author":[{"given":"Mikael","family":"Norman","sequence":"first","affiliation":[{"name":"Division of Pediatrics, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden"},{"name":"Department of Neonatal Medicine, Karolinska University Hospital, Stockholm, Sweden"},{"name":"Swedish Neonatal Quality Register, Ume\u00e5 University Hospital, Ume\u00e5, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Boubou","family":"Hallberg","sequence":"additional","affiliation":[{"name":"Division of Pediatrics, Department of Clinical Science, Intervention, and Technology, Karolinska Institutet, Stockholm, Sweden"},{"name":"Department of Neonatal Medicine, Karolinska University Hospital, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas","family":"Abrahamsson","sequence":"additional","affiliation":[{"name":"Departments of Clinical and Experimental 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Ume\u00e5 University, Ume\u00e5 Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christian","family":"Gadsb\u00f8ll","sequence":"additional","affiliation":[{"name":"Departments of Clinical and Experimental Medicine and Pediatrics, Link\u00f6ping University, Link\u00f6ping, Sweden"},{"name":"Departments of Clinical Sciences and Pediatrics, Lund University and Sk\u00e5ne University Hospital, Lund, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lena","family":"Hellstr\u00f6m-Westas","sequence":"additional","affiliation":[{"name":"Department of Women\u2019s and Children\u2019s Health, Uppsala University, Uppsala, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fredrik","family":"Ingemansson","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Ryhov County Hospital, J\u00f6nk\u00f6ping County Council, Jonkoping, 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Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fredrik","family":"Serenius","sequence":"additional","affiliation":[{"name":"Department of Women\u2019s and Children\u2019s Health, Uppsala University, Uppsala, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Olof","family":"Stephansson","sequence":"additional","affiliation":[{"name":"Division of Clinical Epidemiology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden"},{"name":"Division of Obstetrics and Gynecology, Department of Women\u2019s and Children\u2019s Health, Karolinska Institutet, Stockholm, Sweden"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lennart","family":"Stigson","sequence":"additional","affiliation":[{"name":"Department of Pediatrics, Institute for Clinical Sciences, Queen Silvia Children\u2019s Hospital, Sahlgrenska Academy, G\u00f6teborg University, G\u00f6teborg, 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