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Outcomes in children after mild neonatal hypoxic ischaemic encephalopathy: A population-based cohort study
Anna E Törn1, Susanne Hesselman1,2, Kine Johansen1
1Department of Women's and Children's Health, Uppsala University, Uppsala, Sweden.
Insights
Mild neonatal hypoxic-ischaemic encephalopathy (HIE) significantly increases the risk of cerebral palsy, epilepsy, and death in children up to age six. This study highlights the long-term neurological risks associated with mild HIE in term-born infants.
Area of Science:
- Neonatal neurology
- Pediatric outcomes research
- Public health surveillance
Background:
- Neonatal hypoxic-ischaemic encephalopathy (HIE) is a serious birth complication.
- Mild HIE cases may have long-term neurological sequelae.
- Understanding these risks is crucial for early intervention.
Purpose of the Study:
- To determine if mild neonatal HIE is linked to cerebral palsy, epilepsy, mental retardation, or death.
- To assess these outcomes up to six years of age in term-born infants.
- To quantify the association between mild HIE and adverse neurological outcomes.
Main Methods:
- Population-based cohort study in Sweden (2009-2015) including over 500,000 term infants.
- Mild HIE identified through national health registers.
- Cox proportional hazards regression used to analyze outcomes.
Main Results:
- Infants with mild HIE were four times more likely to experience a composite outcome of cerebral palsy, epilepsy, mental retardation, or death (HR 4.42).
- Significant associations were found with cerebral palsy (HR 21.50) and death (HR 19.10).
- These associations persisted after adjusting for covariates.
Conclusions:
- Mild neonatal HIE is associated with increased neurological morbidity and mortality in childhood.
- Identifying at-risk infants and developing preventative strategies are key challenges.
- This study underscores the importance of monitoring infants with mild HIE for long-term complications.
Objective:
To investigate whether mild neonatal hypoxic ischaemic encephalopathy (HIE) in term born infants is associated with cerebral palsy, epilepsy, mental retardation and death up to 6 years of age.
Design:
Population-based cohort study.
Setting:
Sweden, 2009-2015.
Population:
Live term born infants without congenital malformations or chromosomal abnormalities (n = 505 075).
Methods:
Birth and health data were retrieved from Swedish national health and quality registers. Mild HIE was identified by diagnosis in either the Swedish Medical Birth Register or the Swedish Neonatal Quality Register. Cox proportional hazards regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs).
Main Outcome Measures:
A composite of the outcomes cerebral palsy, epilepsy, mental retardation and death up to 6 years of age.
Results:
Median follow-up time was 3.3 years after birth. Of 414 infants diagnosed with mild HIE, 17 were classified according to the composite outcome and incidence rates were 12.6 and 2.9 per 1000 child-years in infants with and without HIE respectively. Infants with mild HIE was four times as likely to be diagnosed with the composite outcome (HR 4.42, 95% CI 2.75-7.12) compared with infants without HIE. When analysed separately, associations were found with cerebral palsy (HR 21.50, 95% CI 9.59-48.19) and death (HR 19.10, 95% CI 7.90-46.21). HRs remained essentially unchanged after adjustment for covariates.
Conclusions:
Mild neonatal HIE was associated with neurological morbidity and mortality in childhood. Challenges include identifying infants who may develop morbidity and how to prevent adverse outcomes.
