Haemorrhoids are vascular structures in the anal canal which help with stool control. They become pathological or piles when swollen or inflamed. In their normal state, they act as a cushion composed of arterio-venous channels (blood vessels) and connective tissue.
While the exact cause of hemorrhoids remains unknown, a number of factors which increase intra-abdominal pressure, i.e. prolonged straining for constipation, chronic cough, pregnancy, are believed to play a role in their development.
During pregnancy, pressure from the fetus (baby) on the abdomen and hormonal changes cause the hemorrhoidal vessels to enlarge. Delivery also leads to increased intra-abdominal pressures. Pregnant women rarely need surgical treatment, as symptoms usually resolve after delivery.