In the majority of cases, the underlying cause is unknown. Iron metabolism and dopamine, a neurochemical in the brain, are believed to play a role in causing RLS/PLMS.
RLS are often seen in patients with low iron levels, kidney failure, diabetes mellitus and low thyroid hormone.
About one in five pregnant women suffer from RLS in the last three months of pregnancy. The symptoms usually disappear after delivery. Some medications, for example, antidepressants, can trigger and worsen RLS/PLMS.
