It is not known what causes hemorrhoids, but doctors often speak of several main factors. These factors include chronic constipation or diarrhea, sitting on the toilet for a long time and straining during defecation. Hemorrhoids may also appear because of sports. When something heavy is lifted, additional pressure is applied on the area. Women are in danger of having hemorrhoids during pregnancy. This also happens due to increased pressure from the baby. Hemorrhoids are more likely with aging because the tissue becomes weaker. Some people are more likely to get hemorrhoids if other family members have them.