Epilepsy After Electroencephalographically Verified Neonatal Seizures: A Swedish Population-Based Matched Cohort...

To study the risk of postneonatal epilepsy (PNE) after neonatal seizures with electroencephalographic verification, regardless of cause. To investigate which antiseizure medications (ASMs) were used during neonatal hospitalization and to what extent infants were discharged with ASMs from neonatal care.

A Swedish nationwide population-based cohort study, based on national health care registries, including children born from 2009 to 2020.

Neonatal seizures, verified with electroencephalogram and/or amplitude-integrated electroencephalogram.

PNE, with cumulative incidence at 2 and 7 years of age and hazard ratios, excluding children with neonatal onset epilepsy. Follow-up period: January 1, 2009, to December 31, 2021.

The cumulative incidence of PNE was 15.7% (95% confidence interval [CI]: 13.5-18.9) at 2 years and 22.4% (95% CI: 19.8-25.2) at 7 years of age in children with neonatal seizures. For controls, the corresponding incidences were 0.11% (95% CI: 0.05-0.24) and 0.56% (95% CI: 0.36-0.84). The adjusted hazard ratio for PNE following neonatal seizures was 50.3 (95% CI: 33.5-75.5). Phenobarbital was the most commonly used ASM during neonatal hospitalization. The proportions of infants discharged with ASM decreased during the study period from over 70% to 8%, while the risk of PNE remained unchanged.

Children with electroencephalographically verified seizures in the neonatal period are at high risk of developing PNE, vastly surpassing that of the unaffected population. The findings indicate the importance of a standardized clinical follow-up of the affected children and that further research is needed to investigate the impact of seizures per se in specific subgroups.