Indigestion €“ usually referred to by doctors as dyspepsia €“ occurs when acid comes into contact with the lining of the digestive system. Heartburn is caused when acid leaks upwards into the oesophagus, which is uncomfortable because the oesophagus does not have the same protective lining as the stomach. There are many reasons why these two conditions might occur:

• Pregnancy hormones can slow down the digestive process, plus the growing baby often puts pressure on the stomach, pushing the contents upwards
• Weakness of the lower oesophageal sphincter, which normally keeps the contents of the stomach where they're meant to be, and is the cause of gastrooesophageal reflux disease (GORD). This also happens in hiatus hernia, when part of the stomach pushes through the diaphragm of the chest
• Lifestyle factors play a significant role. Being overweight, drinking alcohol, smoking, stress and anxiety can all cause symptoms, as can having a poor diet, either because of the type of food that is being eaten (e.g. fatty foods) or the speed with which it is being consumed
• Some medicines can cause indigestion as a side effect. The most common culprits are NSAIDs such as ibuprofen and aspirin, but many drugs list indigestion as a possible adverse reaction in their patient information leaflets
• Ulcers are erosions of the lining of the stomach or duodenum, which may occur following an infection with the Helicobacter pylori bacteria.

In many cases, more than one factor will be at play. For example, someone may be overweight as a result of frequently eating meals with a high fat content, which in turn has caused them to develop GORD.

Symptoms differ from person to person, but discomfort is usually a feature. If this is experienced in the chest, it is referred to as heartburn, whereas pain slightly lower down may be referred to as indigestion.

It is worth checking what customers mean when they use these terms, as they mean different things to different people. Other symptoms may include nausea, feeling bloated or full, belching and bringing up food into the oesophagus (regurgitation).