Challenging Mild Hypoxic-Ischemic Encephalopathy: Insights Into Neurological Outcomes

Abstract

Objective: This study aims to evaluate the long-term neurological outcomes of neonates diagnosed with mild hypoxic-ischemic encephalopathy (HIE) and compare them with moderate/ severe cases, hypothesizing that a significant proportion of mild HIE cases may experience adverse neurodevelopmental sequelae. Materials and Methods: This was a cross-sectional observational study evaluating the neurodevelopmental outcomes of neonates with mild versus moderate/severe HIE. Maternal, perinatal, and neonatal characteristics along with treatments were documented. Neurological outcomes were assessed via brain MRI, the Ankara Developmental Screening Inventory (ADSI), and developmental milestones. Results: The study included 42 infants, 20 (47.6%) were classified as having mild HIE and 22 (52.4%) as moderate/severe HIE. Baseline characteristics were similar except that moderate/ severe cases had lower 1-minute Apgar scores (median 4 vs. 6; P = .02) and more frequent need for advanced resuscitation (68% vs. 25%; P = .006). All moderate/severe infants received TH vs. none in the mild group. Invasive mechanical ventilation and adjuvant neuroprotective agents were also more frequently used in the moderate/severe group. Magnetic resonance imaging abnormalities consistent with HIE were present in 2/12 mild cases (16.7%) vs. 8/19 (42.1) in moderate/severe cases. There were no significant differences in HIE injury pattern between the 2 groups (P = .197). On ADSI screening, 8/12 (66.7%) mild HIE survivors showed gross motor delay compared with 5/7 (71.4%) moderate/severe survivors. Conclusion: Even infants with mild HIE are at risk of adverse neurological outcomes. The development of more sensitive diagnostic tools could improve treatment strategies and early interventions, ultimately impacting prognosis. With proper recognition, tailored follow-up, and appropriate therapeutic approaches, potential neurodevelopmental impairments in mild HIE cases could be mitigated. © 2025 Elsevier B.V., All rights reserved.