Causes - Restless Leg Syndrome

In many cases, no known cause for restless legs syndrome exists. Researchers suspect the condition may be due to an imbalance of the brain chemical dopamine. This chemical sends messages to control muscle movement.

Heredity
RLS runs in families in up to half the people with RLS, especially if the condition started at an early age. Researchers have identified sites on the chromosomes where genes for RLS may be present.

Stress and pregnancy
Stress tends to worsen the symptoms of RLS. Pregnancy or hormonal changes also may temporarily worsen RLS signs and symptoms. Some women experience RLS for the first time during pregnancy, especially during their last trimester. However, for most of these women, signs and symptoms usually disappear quickly after delivery.

Related conditions
For the most part, restless legs syndrome isn't related to a serious underlying medical problem. However, RLS sometimes accompanies other conditions, such as:

Peripheral neuropathy. This damage to the nerves in your hands and feet is sometimes due to chronic diseases such as diabetes and alcoholism.

Iron deficiency. Even without anemia, iron deficiency can cause or worsen RLS. If you have a history of bleeding from your stomach or bowels, experience heavy menstrual periods or repeatedly donate blood, you may have iron deficiency.

Kidney failure. If you have kidney failure, you also may have iron deficiency, often with anemia. When kidneys fail to function properly, iron stores in your blood can decrease. This, along with other changes in body chemistry, may cause or worsen RLS.