What causes varicose veins?
The cause of varicose veins is unknown but is definitely linked to increase pressure in the veins. There are valves in the veins which prevent the back flow of blood back into the legs. When these valves become damaged/defective, the blood flows backwards and causes swelling and engorgement of the veins.
The causes of varicose veins are unclear. However, some factors have been identified that may contribute to the development of varicose and spider veins: family history of varicose veins, female hormones (internally produced or taken by prescription), pregnancy, trauma, age, obesity, and prolonged standing. Extensive exposure to the sun may also cause spider veins on the face. Please visit Prevention for more information on the causes of “varicose veins”.
A. Heredity is the number one contributing factor causing varicose and spider veins. Women are more likely to suffer from abnormal leg veins. More than 50% of American women may be affected. Hormonal factors including puberty, pregnancy, menopause, the use of birth control pills, estrogen, and progesterone affect the disease. It is very common for pregnant women to develop varicose veins. Pregnancy causes increases in hormone levels and blood volume which in turn cause veins to enlarge. In addition, the enlarged uterus causes increased pressure on the veins. Varicose veins due to pregnancy often improve within 3 months after delivery. However, with successive pregnancies, abnormal veins are more likely to remain. Other predisposing factors include aging, standing occupations, obesity and leg injury.
Increase in the diameter of a vein results in the malfunction of valves inside of the vein that are designed to prevent blood from flowing backward in the vein. An inherited weakness of the vein wall (genetic) and circulating hormones that relax the smooth muscle of the vein wall are the most common causes. Females have high levels of such a hormone, the hormone progesterone. Pregnancies, obesity, hormone replacement therapy, the use of female oral contraceptives as well as occupations that require a standing position are additional causes of varicose veins. Since females usually have multiple risk factors for the development of varicose veins, about three fourths of the persons who have varicose veins are women and 25% are men.
