Women develop spider veins nearly four times as often as men. In fact, about 70% of adult women get spider veins at some time in their lives. Some women are at greater risk due to heredity. Others are likely to get spider veins because of lifestyle.

Women who are pregnant or use oral contraceptives are at risk for spider veins. So are women who experience an increase in estrogen, which is believed to weaken vein walls. Overweight women often get spider veins because they're more likely to develop circulatory problems, diabetes or heart disease. All of these conditions hinder bloodflow to the heart.

Standing for long periods of time also increases the risk of getting spider veins. That’s because it's harder for veins to fight gravity and return blood to the heart. Those who wear high-heeled shoes can stress leg veins by forcing their calf muscles to contract more than usual.

Risk factors for spider veins include:

• Heredity
• Occupations that involve a lot of standing
• Obesity
• Hormonal influences during pregnancy
• Use of oral contraceptives
• Post-menopausal hormone replacement
• Prolonged sitting with legs crossed
• History of blood clots
• Medical conditions such as tumors and constipation that may increase intra-abdominal pressure
• Externally worn garments such as girdles that may increase intra-abdominal pressure

Other minor factors include topical steroids, trauma or injury to the skin, and exposure to ultraviolet rays.