Causes

Often, there's no known cause for RLS. Researchers suspect the condition may be caused by an imbalance of the brain chemical dopamine, which sends messages to control muscle movement.

Heredity

Sometimes RLS runs in families, especially if the condition starts before age 40. Researchers have identified sites on the chromosomes where genes for RLS may be present.

Pregnancy

Pregnancy or hormonal changes may temporarily worsen RLS signs and symptoms. Some women get RLS for the first time during pregnancy, especially during their last trimester. However, symptoms usually disappear after delivery.