Causes
The veins around your anus tend to stretch under pressure and may bulge or swell. Swollen veins (hemorrhoids) can develop from increased pressure in the lower rectum due to:
Straining during bowel movements
Sitting for long periods of time on the toilet
Chronic diarrhea or constipation
Obesity
Pregnancy
Anal intercourse
Low-fiber diet
Hemorrhoids are more likely with aging because the tissues that support the veins in your rectum and anus can weaken and stretch.