Edema refers to swelling because of accumulation of excess fluid. There are various causes as well as subtypes of edema. Thus it is extremely important to do a correct diagnosis before trying to find a cure for water retention feet. In case of Idiopathic Cyclic Edema, it primarily occurs in young menstruating women. In this case water retention feet, legs and abdomen occur after sitting or standing, besides swelling of the face and eyelids due to lying down. This may be due to leakage of blood fluids from the capillaries into fat and skin tissues. Gravity adds to the pressure in the vascular system leading to large weight changes. This condition is called idiopathic orthostatic edema or only idiopathic edema.
The water retention feet can have many other possible causes such as prolonged standing or sitting, which may cause excess fluid accumulation in the feet, ankles as well as lower legs. Venous insufficiency is another common problem of the weakened valves in the veins of the legs, leading to varicose veins as well as build up of fluid.
Chronic lung diseases like emphysema or chronic bronchitis tend to increase the pressure in the blood vessels to the lungs which causes water retention feet and legs. Congestive heart failure is due to decreased pumping action of the heart muscle which leads to fluid buildup in the lungs as well as other parts of the body, resulting in water retention feet and ankles.
Pregnancy also leads to water retention feet because the pregnant uterus tends to put pressure on the vena cava, which is a major blood vessel that returns blood to the heart from the legs. Fluid retention during pregnancy may also be caused by a more serious condition known as preeclampsia. Malnutrition can lead to low protein levels in the body. It is these proteins in the blood which help to hold salt and water inside the blood vessels so that the fluid does not leak out into the tissues. In case the blood protein gets too low, water retention feet, ankles and lower legs occurs.