Reviewed by Brian R. Robinson, MDBlood clots, or venous thromboses (singular: venous thrombosis), are the masses that result when blood coagulates in the veins and remains there.
Blood flows freely through arteries and veins of all sizes. When the body senses injury or trauma, blood thickens, or clots, and stops flowing at the site of distress. In the case of injury or trauma clotting is vital, as it can prevent dangerous levels of blood loss or hemorrhaging. However, clot formation inside healthy blood vessels or the failure of a clot to break down as it should is dangerous and potentially fatal. Such clots are frequent complications of venous diseases such as phlebitis.
Risk factors for blood clots include:
• Prolonged bed rest or immobilization
• Recent surgery or trauma
• Recent childbirth
• Obesity
• Use of medications such as birth control pills or estrogen
