A rare movement disorder developed during pregnancy, characterized by involuntary jerky motion (chorea) and inability to maintain stable position of body parts (athetosis). rheumatic fever and collagen vascular disorders are frequently associated with this disease. chorea may vary from mild to severe and occurs in approximately 1 per 2,000 to 3,000 pregnancies. (From Md Med J 1997 Sep;46(8):436-9)