A hiatus hernia, or hiatal hernia, is when part of the stomach squeezes up into the chest through an opening ("hiatus") in the diaphragm.

The diaphragm is a large, thin sheet of muscle between the chest and the abdomen (tummy).

Hiatus hernia and heartburn

A hiatus hernia itself rarely has any noticeable symptoms. However, it can cause a problem called gastro-oesophageal reflux disease (GORD).

GORD is where stomach acid leaks into the oesophagus (the tube that carries food to the stomach). It can occur if a hiatus hernia prevents the valve at the bottom of the oesophagus from working properly.

Your oesophagus can become severely irritated, because it's not protected against stomach acid. This can cause symptoms such as heartburn, chest pain, an unpleasant sour taste in your mouth, and swallowing problems (dysphagia).

You should see your GP if you have frequent and severe symptoms of GORD.

What causes a hiatus hernia?

It's not exactly clear what causes hiatus hernia, but it may be the result of the diaphragm becoming weak with age, or pressure on the abdomen.

Hiatus hernia can sometimes occur in newborn babies if the stomach or diaphragm doesn't develop properly.

Who's affected

Hiatus hernia can affect anyone, but it's more common in people who are:

• over 50 years of age
• overweight
• pregnant

It's estimated that a third of people over 50 have a hiatus hernia.

There's also a rare type of hiatus hernia that affects newborn babies, which is caused by a congenital defect of the stomach or diaphragm. Congenital means that it is present from birth.

Types of hiatus hernia

There are two main types of hiatus hernia. They are:

• sliding hiatus hernias – hernias that move up and down, in and out of the chest area (more than 80% of hiatus hernias are of this type)
• para-oesophageal hiatus hernias – also called rolling hiatus hernias, where part of the stomach pushes up through the hole in the diaphragm next to the oesophagus (about 5-15% of hiatus hernias are of this type)

These pages mainly focus on sliding hiatus hernias. They can usually be diagnosed using an X-ray or an endoscopy, where a long, thin flexible tube with a light and video camera at one end is used to examine the inside of the body.

Read more about diagnosing a hiatus hernia.

Treating a hiatus hernia

Treatment for a sliding hiatus hernia usually focuses on relieving the symptoms of GORD, such as heartburn.

Lifestyle changes and medication are the preferred treatments. Surgery is usually only recommended as an alternative to long-term medication or if other treatments haven't worked.

Lifestyle advice may include:

• eating smaller, more frequent meals, rather than three large meals a day
• avoiding lying down (including going to bed) for three hours after eating or drinking
• removing any foods or drinks from your diet that make your symptoms worse  

If a hiatus hernia isn't causing any noticeable problems, it doesn't usually need to be treated.

Surgery is used to repair a para-oesophageal hiatus hernia if there's a risk of serious complications.

Read more about treating a hiatus hernia.

Further problems

It's rare for a hiatus hernia to cause complications, but long-term damage to the oesophagus caused by leaking stomach acid can lead to ulcers, scarring and changes to the cells of the oesophagus, which can increase your risk of oesophageal cancer.

Read more about the complications of a hiatus hernia.