Reflux occurs when stomach (gastric) contents back up from the stomach into the esophagus, the tube that connects the mouth to the stomach. More than half of all infants experience episodes of reflux during the first three months of life, according to the National Institutes of Health. In addition, up to 7 million U.S. children and teenagers in the United States experience occasional problems with reflux.

Reflux occurs when the lower esophageal sphincter (LES), which separates the esophagus and stomach, does not close properly and/or is weak. This allows gastric contents to flow into the esophagus, causing a burning sensation in the chest or throat called heartburn. In other cases, gastric contents may be refluxed all the way up into the mouth before they are swallowed again. When stomach acid can be tasted in the back of the mouth, it is called acid indigestion.

Almost everybody experiences occasional reflux, even if they are not aware of it. However, in some cases reflux may indicate a more serious problem. Parents are urged to consult a physician if their child experiences vomiting; especially with heavy volume or projectile vomiting. Breathing problems, poor growth and weight loss due to an inability to retain food are among the other symptoms that indicate a medical problem. 

Certain factors may be more likely to trigger reflux in infants. Overfeeding babies or holding them flat instead of upright during feedings can trigger reflux. In rare cases, a child’s reflux problem may stem from a narrowing of the esophagus or a problem with the position of the intestines, a condition known as malrotation. An allergy or intolerance to milk is also a cause of reflux in some children.

Children are less likely to tolerate investigative studies that are usually performed on adults with reflux (e.g., esophageal pH monitoring). As a result, a diagnosis typically involves a physician’s judgment based on a physical examination and the child’s medical history. To rule out anatomical abnormalities, a physician may order an x-ray of the esophagus and the stomach. Children who are diagnosed with a reflux disorder may be referred to a pediatric gastroenterologist or other specialist who has expertise in treating reflux disorders.