The primary reason GER occurs in neonates is due to the immaturity of the lower esophageal sphincter (LES). In newborns, the LES is often not fully developed, which means it may not close properly. This allows stomach contents, including acid, to flow back into the esophagus. Other contributing factors can include the horizontal position of infants, their liquid diet, and underdeveloped gastrointestinal motility.
