Is there any particular cause for the development of hemorrhoids?

Straining to have BM: When the stool is small it requires more effort to pass. This bearing down effort to move stool is what causes the dilation of the hemorroidal veins. With chrnoic straiingn during bowel movement the veins get weaker and weaker and dilate more. A high fiber diet makes large soft stools that are easy to pass and hemorroids less likely to form.

Several: Chronic constipation, anal intercourse, straining (pushing) hard with bowel movements, and vaginal childbirth (being the mom that is delivering the baby) are the most common causes.