What causes hemrrhoids to bleed? is it because of irritation from wiping or something else? pregnant and wondering why it bleeds after a bowel movt?

Sure its hemorrhoid?: Bleeding per rectum may originate in the anal canal, the rectum, or further up the line. Frequent anal sources of bleeding include hemorrhoids & fissures, that may respond to modifying stool texture (fiber, softeners) and topical agents, or require further intervention. Similar bleeds can be seen with anal & rectal cancer, infections, ischemic colitis, diverticular bleeds, inflammatory bowel, etc.