Haemorrhoids (piles) are usually caused by excess pressure on blood vessels in and around the anus.

If you are constipated and strain while trying to pass stools, it can put pressure on blood vessels in your back passage, making them inflamed and swollen.

Who's at risk

Factors which increase your chances of getting haemorrhoids include:

• being overweight
• prolonged constipation, often due to a lack of fibre in your diet
• prolonged diarrhoea
• regularly lifting heavy objects  
• being pregnant - which can place increased pressure on your pelvic blood vessels, causing them to enlarge (the haemorrhoids will usually disappear after you give birth)
• being over 50 years of age - as you get older, your body's supporting tissues get weaker, increasing your risk of developing haemorrhoids
• a family history of haemorrhoids - you may be predisposed (have an increased tendency) to developing haemorrhoids, for example, due to having weak blood vessels