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Pediatrics. 2017 Dec;140(6). pii: e20171264. doi: 10.1542/peds.2017-1264. Epub 2017 Nov 21.

Survival in Very Preterm Infants: An International Comparison of 10 National Neonatal Networks.

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Department of Pediatrics and Adolescent Medicine, Turku University Hospital, Kiinamyllynkatu, Turku, Finland;
Department of Clinical Medicine, University of Turku, Turku, Finland.
National Quality Registry for Neonatal Care, Department of Pediatrics/Neonatal Services, University Hospital of Umeå, Umeå, Sweden.
Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada.
Maternal-Infant Care Research Centre, and Department of Pediatrics, Mount Sinai Hospital, Toronto, Ontario, Canada.
United Kingdom Neonatal Collaborative, Neonatal Data Analysis Unit, and Section of Neonatal Medicine, Department of Medicine, Imperial College London, Chelsea and Westminster Hospital, London, United Kingdom.
Gertner Institute for Epidemiology and Health Policy Research, Sheba Medical Center, Tel Hashomer, Israel.
Department of Social Medicine, National Center for Child Health and Development, Tokyo, Japan.
Maternal and Perinatal Center, Tokyo Women's Medical University, Tokyo, Japan.
Royal Hospital for Women, and National Perinatal Epidemiology and Statistics Unit, University of New South Wales, Randwick, Australia.
Department of Pediatrics, University of Otago, Christchurch, New Zealand.
Department of Neonatology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.
Health Research Institute La Fe, Avenida Fernando Abril Martorell, Valencia, Spain; and.
TIN Toscane Online, Unit of Epidemiology, Meyer Children's University Hospital, Florence, Italy and Regional Health Agency of Tuscany, Florence, Italy.
Department of Pediatrics and Adolescent Medicine, Turku University Hospital, Kiinamyllynkatu, Turku, Finland.



To compare survival rates and age at death among very preterm infants in 10 national and regional neonatal networks.


A cohort study of very preterm infants, born between 24 and 29 weeks' gestation and weighing <1500 g, admitted to participating neonatal units between 2007 and 2013 in the International Network for Evaluating Outcomes of Neonates. Survival was compared by using standardized ratios (SRs) comparing survival in each network to the survival estimate of the whole population.


Network populations differed with respect to rates of cesarean birth, exposure to antenatal steroids and birth in nontertiary hospitals. Network SRs for survival were highest in Japan (SR: 1.10; 99% confidence interval: 1.08-1.13) and lowest in Spain (SR: 0.88; 99% confidence interval: 0.85-0.90). The overall survival differed from 78% to 93% among networks, the difference being highest at 24 weeks' gestation (range 35%-84%). Survival rates increased and differences between networks diminished with increasing gestational age (GA) (range 92%-98% at 29 weeks' gestation); yet, relative differences in survival followed a similar pattern at all GAs. The median age at death varied from 4 days to 13 days across networks.


The network ranking of survival rates for very preterm infants remained largely unchanged as GA increased; however, survival rates showed marked variations at lower GAs. The median age at death also varied among networks. These findings warrant further assessment of the representativeness of the study populations, organization of perinatal services, national guidelines, philosophy of care at extreme GAs, and resources used for decision-making.

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