Mild hypoxic ischaemic encephalopathy and long term neurodevelopmental outcome - A systematic review

Area of Science:

• Neonatal neurology
• Neurodevelopmental disorders
• Perinatal medicine

Background:

• Hypoxic ischaemic encephalopathy (HIE) is a major cause of long-term neurodisability in newborns.
• Therapeutic hypothermia (TH) is a standard treatment, but its efficacy in mild HIE cases is not well-established.
• Infants with mild HIE represent 50% of cases and are typically excluded from TH.

Purpose of the Study:

• To review the existing evidence on neurodevelopmental outcomes in term infants diagnosed with mild HIE.
• To assess the risk of abnormal outcomes in this specific patient population.

Main Methods:

• A systematic literature search was conducted across Medline, Embase, and Cochrane Clinical Trials databases.
• Included studies required clear HIE grading at birth and neurodevelopmental assessment at ≥18 months.
• Abnormal outcome was defined as death, cerebral palsy, or neurodevelopmental test scores >1 SD below the mean.

Main Results:

• Twenty studies met the inclusion criteria.
• Abnormal outcomes were reported in 25% (86/341) of infants with mild HIE.
• Insufficient evidence was found to evaluate the impact of TH on outcomes in mild HIE.

Conclusions:

• A substantial proportion of infants with mild HIE experience adverse neurodevelopmental outcomes.
• The findings highlight a potential unmet need for intervention or closer monitoring in this group.
• Further research is warranted to explore optimal management strategies for mild HIE.