Factors Influencing Breastfeeding Outcomes Following Neonatal Hypoxic Ischaemic Encephalopathy: A Mixed Methods Systematic Review

Background: Hypoxic ischaemic encephalopathy (HIE) is the most frequently occurring neonatal brain injury in term-born infants. Families affected by HIE can face significant breastfeeding and lactation challenges. Aims: This systematic review aims to improve our understanding of these challenges and identify potential solutions by answering the question: What factors influence breastfeeding and lactation outcomes after neonatal HIE? Methods: This systematic review used a convergent integrated analysis mixed methods design. Eleven databases were searched for qualitative, quantitative, and mixed methods papers meeting specified criteria (e.g., born ≥ 34 weeks gestation) in November 2022 and again in July 2023 and April 2025. Full methods are registered on PROSPERO https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023375506. Of the 3393 titles and abstracts screened, 455 were identified for full-text screening and 10 were included in the review. An additional seven papers were found via reference lists and citation checking, resulting in a total of 17 included studies. Results: Five categories of potentially influencing factors were identified: infant medical factors, neuroprotective interventions, feeding during therapeutic hypothermia, support for expressing milk, and parent–infant closeness in the neonatal phase. However, significant evidence gaps were demonstrated, including the influence of environmental and social factors, interventions for lactation support and breastfeeding skills, and qualitative and mixed methods studies specifically focused on breastfeeding and lactation following neonatal HIE. Conclusion: Current research is insufficient to inform our understanding of factors influencing breastfeeding and lactation outcomes following HIE. High-quality breastfeeding and lactation-specific research is urgently needed to inform information sharing and intervention development for HIE-affected families.