How does the lower esophageal sphincter (LES) contribute to infant reflux?

The lower esophageal sphincter (LES) is a crucial muscle that helps prevent the backflow of stomach contents into the esophagus. In infants, the LES is often not fully mature, which means it may not function as effectively as it does in older children and adults. This immaturity can lead to increased instances of gastroesophageal reflux, commonly known as reflux.

A less mature LES may not maintain adequate pressure to keep the stomach contents from escaping into the esophagus, especially during feeding or when the infant is lying down. This physiological immaturity is a normal developmental stage and is often self-resolving as the infant grows and the LES matures. Understanding this aspect helps caregivers and healthcare professionals differentiate between normal physiological reflux and conditions that may require intervention.