EXPRESS study shows significant regional differences in 1-year outcome of extremely preterm infants in Sweden

Acta Paediatr. 2014 Jan;103(1):27-37. doi: 10.1111/apa.12421. Epub 2013 Oct 30.


Aim: The aim of this study was to investigate differences in mortality up to 1 year of age in extremely preterm infants (before 27 weeks) born in seven Swedish healthcare regions.

Methods: National prospective observational study of consecutively born, extremely preterm infants in Sweden 2004-2007. Mortality was compared between regions. Crude and adjusted odds ratios and 95% CI were calculated.

Results: Among 844 foetuses alive at mother's admission for delivery, regional differences were identified in perinatal mortality for the total group (22-26 weeks) and in the stillbirth and perinatal and 365-day mortality rates for the subgroup born at 22-24 weeks. Among 707 infants born alive, regional differences were found both in mortality before 12 h and in the 365-day mortality rate for the subgroup (22-24 weeks) and for the total group (22-26 weeks). The mortality rates were consistently lower in two healthcare regions. There were no differences in the 365-day mortality rate for infants alive at 12 h or for infants born at 25 weeks. Neonatal morbidity rates among survivors were not higher in regions with better survival rates. Perinatal practices varied between regions.

Conclusion: Mortality rates in extremely preterm infants varied considerably between Swedish healthcare regions in the first year after birth, particularly between the most immature infants.

Keywords: Cohort study; Extremely preterm infant; Morbidity; Mortality; Outcome.

Publication types

  • Comparative Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Humans
  • Infant Mortality*
  • Infant, Extremely Premature*
  • Infant, Newborn
  • Male
  • Middle Aged
  • Perinatal Mortality*
  • Prospective Studies
  • Sweden / epidemiology
  • Young Adult