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.
What are the symptoms?
Reflux happens very commonly in babies, and many don’t show any symptoms.
The most common symptom of reflux is a small spill of milk after a feed. Sometimes when the milk mixes with stomach acid then washes back up the oesophagus, the resulting regurgitation causes pain.
Other symptoms may include distress or discomfort with feeds, crying during or after feeds or more significant vomiting with feeds. Some babies will refuse or vomit so much of their feed they are unable to gain weight. Some even lose weight.
It’s important to bear in mind many of these symptoms can be caused by issues other than reflux such as colic, cow’s milk protein intolerance, infections and underlying gastrointestinal disorders. A medical review is useful to help look for any other causes prior to making a diagnosis of reflux.
Silent reflux is usually used to describe a baby who is regurgitating a meal into the oesophagus but not as far as the mouth.
It can still lead to discomfort and distress, but doesn’t cause a vomit or a spill of milk. In this way, it can be difficult for a parent to identify the cause of the distress.
This is because the particular features of babies which cause reflux (lying down, consuming only liquid, having relatively underdeveloped muscles and a shorter oesophagus) improve with time. Additionally, some of the treatments themselves can be harmful or may not work.