Risk factors for venous insufficiency are numerous but the main two causes are heredity and pregnancy. The risk of developing superficial venous insufficiency increases with each successive pregnancy. This is related to the increase in the total blood volume in the veins and in the increased pelvic pressure caused by the gravid uterus. The third trimester is when most of the severe venous changes in the legs occur.
Other risk factors include female gender (women are nearly twice as likely to develop venous insufficiency as men); advanced age, obesity, and occupations which require prolonged standing without walking such as: nursing, pharmacy, teaching and other professions with similar activity profiles.
Deep vein thrombosis (DVT) is the major risk factor for developing deep vein insufficiency. When the clots in the deep system are dissolved, the valves are often scarred against the walls and do not close tightly. The result is a valve or valves which do not meet in the middle of the vein and reflux of blood back down toward the feet occurs. Deep vein insufficiency is treatable with elevation and compression hose, however is not treatable by endovenous techniques such as endovenous closure. Fortunately, only a small percentage of patients with symptomatic venous insufficiency have deep system involvement.