TOPLINE:

Infant mortality declined substantially in Norway between 2009 and 2020, alongside improved survival among infants born extremely preterm and significant decreases in the risk for mortality associated with prematurity, congenital malformations, and sudden infant death syndrome.

METHODOLOGY:

• Researchers conducted a population-based cohort study to examine temporal trends in infant mortality stratified by the timing and main causes of death and variations by gestational age.
• They used data from two linked heath registers from Norway and identified 676,931 live-born infants who died before reaching 1 year of age between 2009 and 2020.
• Infant deaths were categorised on the basis of the timing of death as early neonatal (0-24 hours and 2-7 days), late neonatal (8-28 days), and postneonatal (29-365 days).
• Causes of death were classified into the following six categories: prematurity-related deaths, asphyxia or neonatal encephalopathy, congenital malformations, sudden infant death syndrome, infections, and other causes.

TAKEAWAY:

• A total of 1583 infants died before reaching 1 year of age. The overall infant mortality rate declined from 2.9 to 1.7 per 1000 live-born infants between 2009 and 2020, with neonatal mortality decreasing from 2.0 to 1.3 per 1000 live-born infants and postneonatal mortality decreasing from 0.9 to 0.4 per 1000 live-born infants.
• Most infants (69.2%) died within the first 28 days after birth, with 30.6% died within the first 24 hours, 19.6% died between 2 and 7 days, and 19.1% died between 8 and 28 days; however, 30.8% of deaths occurred during the postneonatal period.
• Prematurity-related conditions were the leading cause of death (39.6%) but showed a significant reduction in the risk over time (relative risk [RR], 0.96; P < .001). Significant declines were also observed for deaths due to congenital malformations and chromosomal abnormalities (RR, 0.97; P = .023) and sudden infant death syndrome (RR, 0.92; P = .006); however, mortality related to asphyxia, infection, and other causes showed no significant change over time.
• Infants born extremely preterm (22-27 weeks of gestation) had the highest risk for death but experienced the greatest improvement, with a 30% relative reduction in mortality (RR, 0.70; 95% CI, 0.58-0.84), falling from 363 to 227 deaths per 1000 live births.

IN PRACTICE:

"[The study] findings identify targets for prevention, as well as new areas of research, and emphasise the critical vulnerability of the early neonatal period," the authors wrote.

SOURCE:

This study was led by Beate Horsberg Eriksen, Møre and Romsdal Hospital Trust, Ålesund, Norway. It was published online on April 16, 2026, in Acta Paediatrica.

LIMITATIONS:

The high-income setting limited global applicability; most cause-of-death classification systems lacked validation as national or international standards, and socioeconomic data were unavailable, which could have identified specific high-risk groups.

DISCLOSURES:

This study received funding from the Møre and Romsdal Hospital Trust, Research Department, and the Norwegian SIDS and Stillbirth Society. The authors declared having no conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.