Severe Neonatal Morbidity Across Gestational Age: Monitoring Infants at High Risk of Mortality.

Abstract

Aim: This study aimed to quantify temporal trends in severe neonatal morbidity (SNM) and examine its association with neonatal mortality, stratified by gestational age.

Methods: This study included all live births in Sweden from 2007 to 2021. SNM types and subtypes were identified based on diagnoses and procedure codes for births ≥ 22 weeks' gestation, including complications within 27 days. Rates were calculated by gestational age, and temporal changes were assessed using rate ratios (RR) and 95% confidence intervals (CI). Adjusted relative risks (aRR) of neonatal death were also estimated.

Results: From 2007 to 2021, 47,048 (2.8%) cases of SNM were identified, rising from 2.2% in 2007 to 3.6% in 2021, mainly due to increased resuscitation/mechanical ventilation rates across all gestational ages. Infections rose among infants born at ≥ 37 weeks (0.59% in 2007-2011 to 0.77% in 2017-2021, RR 1.30, 95% CI, 1.24-1.37), but declined in those born at 22-31 weeks. Neurological morbidity, especially seizures, slightly increased in term and moderately preterm infants. Except for infants born at 22-27 weeks, neonatal mortality risks among infants with SNM were higher in infants with greater gestational ages.

Conclusion: Despite advances in neonatal care, SNM prevalence in Sweden increased from 2007 to 2021 across all gestational ages.