Hemorrhoids are vascular cushions in the anal canal. Hemorrhoids are normal. However, if these vascular cushions become enlarged or inflamed, symptoms, such as bleeding, discomfort, swelling or protrusion, may result. Hemorrhoids become enlarged from increased pressure in the lower rectum. Factors causing increased pressure include: constipation, straining, prolonged sitting on the toilet, pregnancy, obesity and anal intercourse. Hemorrhoids can also enlarge as you get older because the surrounding tissues in your rectum weaken and stretch with age.