“Gastroesophageal reflux (GER) happens when stomach contents come back up into the esophagus causing heartburn. Gastroesophageal reflux disease (GERD) is a more serious and long-lasting form of GER and may prevent an infant from feeding.” nih.gov
“GER is a normal physiologic process that occurs throughout the day in infants and less often in children and adolescents” (AAFP 2015). GER doesn’t require treatment and resolves by 12 months of age. By definition, GER is not troublesome to the patient. The infant or child is growing well, vital signs are normal, weight gain on the growth curve is normal and there are no respiratory or nervous system problems. G.I. symptoms may include regurgitation at meal time but these symptoms are minimal and not bothersome to the patient.
GERD, on the other hand, goes beyond something physiologic to a disease by causing reflux symptoms that are troublesome to the patient and may lead to medical complications. The infant/child may have poor weight gain, weight loss or weight faltering. The infant or child may have troublesome gastrointestinal, respiratory, and nervous system disease.
Clinical Features that distinguish between GER and GERD, from AAFP table.
Further Reading / Reference
https://www.niddk.nih.gov/health-information/digestive-diseases/acid-reflux-ger-gerd-infants
Am Fam Physician. 2015 Oct 15;92(8):705-717.