Extra pressure on the blood vessels in the back passage can restrict blood flow. Most commonly, this extra pressure comes from constipation. When someone strains to produce a bowel movement over an extended period of time, it can cause the blood vessels to become swollen and enlarged. Another common cause of piles is pregnancy. The weight of the maturing foetus can press upon the back passage, restricting blood flow and causing the blood vessels to swell.
Ways extra pressure may be applied to the back passage:
Constipation
These piles develop around the outside edge of the anus. They are less common than internal piles, and do not usually cause pain or other symptoms.
Pregnancy
A growing foetus, as well as exertion of labour, can put extra pressure on the back passage.
Being overweight
Carrying around extra body weight (as well as a poor diet) may lead to piles.
Heavy lifting
Straining the lower body may damage the tissue and blood vessels of the back passage.
Prolonged diarrhoea
The extra force from a great deal of bowel movements may damage and swell the blood vessels.
As with many other conditions, piles may occur more often in people that have a family history of this problem. But this doesn't mean that having a family history of piles guarantees you'll get them too; often, it is a combination of causes that leads to piles.
To understand piles better, get to know the Symptoms