Kirsten Thompson, University of Western Australia
Gastro-oesophageal reflux is a condition that affects up to half of all babies under three months of age.
It can happen multiple times a day, particularly after feeds. It happens when food is swallowed into the stomach, but then regurgitates back into the oesophagus (food pipe). Sometimes it then drops back into the stomach (and down the gastrointestinal tract) or sometimes it washes back up to the mouth or further, causing a vomit or spill of feed.
Why do so many babies get reflux?
When we swallow food, multiple factors usually combine to keep it in the stomach.
First, people generally sit up to eat, so gravity assists the food staying down.
Second, we usually eat food with enough weight and density to stay in the stomach.
Third, we have a lower oesophageal sphincter, which is a muscular band around the lower end of the oesophagus, helping stop food coming back up.
Fourth, our oesophagus is quite long, helping to increase the distance food would have to travel to come back up.
In babies, these factors are not there. They lie down most of the time, consume only liquid, their muscles are not yet as well developed as they will become, and their oesophagus is still relatively short. As a result, babies are far more likely to have some degree of regurgitation of their milk.
Reflux isn’t necessarily a bad thing for babies. If they have swallowed a large amount of milk (and air) during a feed, reflux is a way the body can help to reduce the pressure, and relieve the discomfort of an overfull stomach.