Pregnancy and constipation are the common causes of hämorrhoiden . This is mainly because the mentioned conditions increase pressure to the veins surrounding the anus or the rectum and causing them to swell. In pregnancy, stretching of the uterus increases pressure on the hemorrhoidal veins. For most pregnant women hemorrhoids disappear after giving birth. As for constipation straining during bowel movement damages the blood vessels surrounding the anus thus one develops hemorrhoids.
Lack of fiber in your diet can also cause this condition. It is therefore advisable that to avoid hemorrhoids one should take a diet rich in fiber.
Other causes of hemorrhoids are chronic liver conditions, aging (which brings about weakening of anal and rectal tissue therefore causing hemorrhoids), heredity, obesity, exercise by lifting heavy objects, overuse of laxatives which subsequently damage bowel functions and abdominal pressure. Sitting on the toilet for long has also been said to cause for hemorrhoids.