Has survival after extremely preterm birth changed in Sweden from 2004-2007 to 2014-2016?
In this comparison of 2 birth cohorts in Sweden that included 2205 births at 22-26 weeks’ gestational age, 1-year survival among those born alive in 2004-2007 was 70% compared with 77% for those born alive in 2014-2016 and the difference was statistically significant.
In Sweden, 1-year survival after extremely preterm birth improved between 2004-2007 and 2014-2016.
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.
To compare survival of extremely preterm infants born during 2004-2007 with survival of infants born during 2014-2016.
Design, Setting and Participants
All births at 22-26 weeks’ gestational age (n = 2205) 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.
Delivery at 22-26 weeks’ gestational age.
Main Outcomes and Measures
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).
During 2004-2007, 1009 births (3.3/1000 of all births) occurred at 22-26 weeks’ gestational age compared with 1196 births (3.4/1000 of all births) during 2014-2016 (P = .61). One-year survival among live-born infants at 22-26 weeks’ gestational age was significantly lower during 2004-2007 (497 of 705 infants [70%]) than during 2014-2016 (711 of 923 infants [77%]) (difference, −7% [95% CI, −11% to −2.2%], P = .003). One-year survival among live-born infants at 22-26 weeks’ 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, −6% [95% CI, −11% to −1.7%], P = .008).
Conclusions and Relevance
Among live births at 22-26 weeks’ gestational age in Sweden, 1-year survival improved between 2004-2007 and 2014-2016.
Norman M, Hallberg B, Abrahamsson T, et al. Association Between Year of Birth and 1-Year Survival Among Extremely Preterm Infants in Sweden During 2004-2007 and 2014-2016. JAMA. 2019;321(12):1188–1199. doi:10.1001/jama.2019.2021
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