Physiology of gastroesophageal reflux in the neonate.

Gastroesophageal reflux is physiologically normal in infants but can become gastroesophageal reflux disease when it leads to significant symptoms (persistent vomiting, weight loss, feeding difficulties). Gastroesophageal reflux disease is highly prevalent among infants and contributes to increased health care utilization. There are several physiologic and lifestyle factors that predispose infants to a higher degree of gastroesophageal reflux and disease related to it. Preterm infants and infants admitted to the neonatal intensive care unit, are a special population that have unique risk factors for gastroesophageal reflux disease and have a high prevalence of gastroesophageal reflux disease. To better understand gastroesophageal reflux in infants and neonates with medical complexity, this article will first review the physiology of typical swallowing and motility of the upper gastrointestinal tract in infants. Then, the pathophysiology of gastroesophageal reflux in infants will be reviewed. Finally, this article also addresses specific physiological differences in preterm infants that are important to aid in the understanding of management of gastroesophageal reflux disease in this specific population.