Haemorrhoids (piles) - Causes of piles (haemorrhoids)

The exact cause of piles (haemorrhoids) is unclear, but many cases are thought to be linked to increased pressure in blood vessels in and around the anus.

This pressure can cause the blood vessels in your back passage to become swollen and inflamed.

Who's at risk

Factors that increase your chance of getting haemorrhoids include:

• being overweight or obese
• persistent constipation, often due to a lack of fibre in your diet
• prolonged diarrhoea
• regularly lifting heavy objects  
• a persistent cough or repeated vomiting
• prolonged sitting down
• being pregnant, which can place increased pressure on your pelvic blood vessels, causing them to enlarge (the haemorrhoids will usually improve after you give birth)
• being over 45 years of age – as you get older, your body's supporting tissues get weaker, increasing your risk of haemorrhoids
• a family history of haemorrhoids, which could mean you're more likely to get them