External hemorrhoids can be seen or felt easily around the anal opening. When the swollen veins are scratched or broken by straining or rubbing, they bleed. Veins in the rectum and around the anus tend to expand under pressure. Hemorrhoids can result from too much pressure on these veins. Flare-ups of hemorrhoids may occur during periods of stress or as a result of overuse of alcohol.
Some people inherit a tendency to have hemorrhoids.
Pregnant women should try to avoid becoming constipated because they are more likely to have hemorrhoids during pregnancy. In the last trimester of pregnancy, the enlarged uterus pressing on blood vessels in the anal area can cause hemorrhoids. Also, the strain of childbirth sometimes leads to hemorrhoids after delivery. Your health care provider will examine your rectum and anus. He or she may use a lighted viewing tool called a proctoscope or anoscope to look inside the rectum.