Preterm infants experience a multitude of prenatal and postnatal stressors, resulting in cumulative stress exposure, which may jeopardize the timely attainment of developmental milestones, such as achieving oral feeding. Up to 70% of preterm infants admitted to the neonatal intensive care unit experience challenges while initiating oral feeding. Oral feeding skills require intact neurobehavioral development. Evolving evidence demonstrates that cumulative stress exposure results in epigenetic modification of glucocorticoid-related genes. Epigenetics is a field of study that focuses on phenotypic changes that do not involve alterations in the DNA sequence. Epigenetic modification of glucocorticoid-related genes alters cortisol reactivity to environmental stimuli, which may influence neurobehavioral development, and is the essence of the evolving field of Preterm Behavioral Epigenetics. It is plausible that early-life cumulative stress exposure and the ensuing epigenetic modification of glucocorticoid-related genes impair neurobehavioral development required for achievement of oral feeding skills in preterm infants.
The purpose of this article is to build upon the evolving science of Preterm Behavioral Epigenetics and present a conceptual model that explicates how cumulative stress exposure affects neurobehavioral development and achievement of oral feeding skills through epigenetic modification of glucocorticoid-related genes.
Using the Preterm Behavioral Epigenetics framework and supporting literature, we present a conceptual model in which early-life cumulative stress exposure, reflected by DNA methylation of glucocorticoid-related genes and altered cortisol reactivity, disrupts neurobehavioral development critical for achievement of oral feeding skills.
Implications for Practice and Research:
Future investigations guided by the proposed conceptual model will benefit preterm infant outcomes by introducing epigenetic-based approaches to assess and monitor preterm infant oral feeding skills. Furthermore, the proposed model can guide future investigations that develop and test epigenetic protective interventions to improve clinical outcomes, representing an innovation in neonatal care.