Women who are obese and taking the combined oral contraceptive pill have 12 to 24 times greater risk of developing a leg-vein blood clot than those not taking the pill and who are not overweight, according to a recent review of research. Other studies have found a lower but still increased risk.
This kind of blood clot, known as a deep venous thrombosis (DVT), can cause pain, swelling and redness of the affected leg. Usually this pain happens in the calf or thigh. Fortunately, most DVTs aren’t fatal – but they are serious and need to be treated urgently. In a small number of cases, part of the clot can break off and travel to the lungs which can be life threatening.
