Varicose veins are superficial veins that have become large and tortuous due to increased pressure of blood inside them. Although varicose veins can appear anywhere in the body, they are most commonly found in the legs. If you are pregnant, you are especially prone to developing varicose veins. It is estimated that up to 40 percent of pregnant women will eventually have them. To better learn how varicose veins form, it would be best to first understand how the normal venous system of the body works.
Blood in the vessels moves unidirectionally--from the heart, then through arteries and capillaries, and finally through veins back to the heart. Unlike arteries, veins are thin walled and stretchy, so blood will tend to accumulate in veins unless mechanisms are put in place to prevent the pooling of blood.
Every time that the muscles surrounding veins contract, they act like pumps that keep blood flowing toward the heart. Veins are also equipped with one-way valves that prevent the backflow of the blood when the muscles start to relax. Varicose veins develop when the one-way valves start to fail, causing the column of blood in the legs to pool in the veins.
During pregnancy, blood levels of the hormone progesterone rise in the body. One of the interesting effects of progesterone is to relax smooth muscle. Veins, which are composed of a middle layer of smooth muscles, become more dilated and tortuous as a result of prolonged exposure to progesterone during pregnancy.
As veins progressively dilate, valves fail to appose completely and there is a slight space separating the valve leaflets. Consequently, gravity causes some blood to leak through the valves and pool in the most dependent areas of the body, such as the legs during ambulation or prolonged walking.
Adding to the problem of varicose veins during pregnancy is the large gravid uterus that compresses the veins in the pelvic region. The compression causes the pressure in the superficial veins of the legs to increase, leading to the formation of varicose veins. Sometimes, the pressure becomes high enough to cause some damage to the valve leaflets themselves. This explains why, if you are a female, you are more at risk for varicose veins even when you are not pregnant.
The dilated, squiggly, bluish-green varicose veins in the legs are quite unsightly. However, apart from cosmetic reasons, varicose veins can cause an achy and heavy sensation in the legs. Varicose veins can also get itchy, and constant scratching can cause wounds and ulcerations to form.
The main factor causing and maintaining varicose veins during pregnancy is pregnancy itself. The pregnant uterus and excessive blood levels of progesterone are conditions unique to pregnancy and expected to be gone once the pregnancy is over and the baby is delivered. It is not recommended that varicose veins be removed during pregnancy because they are expected to disappear after delivery of the baby. Warm compresses may be applied to relieve the achy sensation associated with varicose veins. Unfortunately, varicose veins tend to recur with each succeeding pregnancy.