Many factors increase a person's chances of developing varicose or spider veins. These include:

• Increasing Age
• Having family members with vein problems or being born with weak vein valves
• Hormonal changes. These occur during puberty, pregnancy, and menopause. Taking birth control pills and other medicines containing estrogen and progesterone also increase the risk of varicose or spider veins
• Pregnancy. During pregnancy there is a huge increase in the amount of blood in the body. This can cause veins to enlarge. The expanding uterus also puts pressure on the veins. Varicose veins usually improve within 3 months after delivery. A growing number of abnormal veins usually appear with each additional pregnancy
• Obesity, leg injury, prolonged standing and other things that weaken vein valves
• Sun exposure, which can cause spider veins on the cheeks or nose of a fair-skinned person

Why do varicose veins and spider veins usually appear in the legs?