The precise cause of varicose veins is unknown, but the main problem is probably a weakness in the walls of superficial veins. This weakness may be inherited. Over time, the weakness causes the veins to lose their elasticity. They stretch and become longer and wider. To fit in the same space that they occupied when they were normal, the elongated veins become convoluted. More important than the elongation is the widening of the veins, which causes the valve cusps to separate. When the person stands, the blood is pulled backward by gravity and is not stopped because the valve cusps are separated. Thus, blood flows backward, rapidly filling the veins and causing the thin-walled, convoluted veins to enlarge even more. Some of the connecting veins, which normally allow blood to flow only from the superficial veins into the deep veins, also enlarge. If they enlarge, their valve cusps also separate. Consequently, blood squirts backward into the superficial veins when the muscles squeeze the deep veins, causing the superficial veins to stretch further.

Symptoms and Complications
Besides being unsightly, varicose veins commonly ache. Many people, even some with very large veins, have no pain. The lower part of the leg and ankle may itch, especially if the leg is warm after a person has been wearing socks or stockings. Itching can lead to scratching and can cause redness or a rash, which is often incorrectly attributed to dry skin. The pain is sometimes worse when varicose veins are developing than when they are fully stretched.

Only a small percentage of people with varicose veins have complications, such as dermatitis, inflammation of the veins (phlebitis), or bleeding. Dermatitis produces a red, scaling, itchy rash or a brown area, usually on the inside of the leg above the ankle. Scratching or a minor injury, particularly from shaving, can cause bleeding or development of a painful ulcer that does not heal. Ulcers may also bleed. Phlebitis may occur spontaneously or result from an injury. Although usually painful, phlebitis that occurs with varicose veins is rarely harmful.

The unwelcome truth is that spider veins and varicose veins mostly happen to women. It’s not exclusively the case but generally speaking – as a woman you’re more likely to get problems with vein weakness than a man is. And the reasons lie at the very root of your femininity – the female hormone estrogen.

Varicose Veins - Why They're Worse For Women

If you think about it – the veins in your legs are some of the longest in the human body. So your blood has to go on quite a journey back to the heart and for many people most of the time this doesn’t present a problem.

Your leg veins are well equipped to get the blood you need back to your heart. The human body truly is an amazing thing. Because leg veins need to be so long they come with a series of tiny valves – up to 20 depending on how long your legs are. These minute valves control the flow of blood from your legs back to your heart.

It’s a bit like the locks in a canal – the blood is allowed to collect at various points – and then move on when your body is ready.

Unfortunately for some of us – these little valves can become faulty – so blood that was making its way up to your heart trickles back down. Over time sections of your veins can swell as the excess blood starts to collect.

Pregnancy adds to the strain. Your body goes into overdrive – pumping out a huge amount of hormones into your body and increasing the amount of blood moving through your veins by as much as 20 percent. The result – overworked and weakened valves.

The weight of your growing baby also has an impact making it more difficult for the blood traveling back to your heart to get there – and even more likely that some of it will simply accumulate in your legs.

And – wouldn’t you just know it – age makes things worse. Some of us get to our fiftieth birthdays without so much as one spider vein or varicose vein in sight – only to suddenly start experiencing problems.

The reasons are not entirely clear but it has something to do with the fact that as you get older your blood vessels can lose some elasticity and bounce.

The causes of spider veins and varicose veins are many and varied – but some of it has to do with the simple fact of being born a woman.