[Mona Lisa syndrome: idiopathic facial paralysis during pregnancy].

Mona Lisa has been pregnant shortly before the famous painting of Leonardo da Vinci was created (1503-1506). Recently, it has been speculated that Mona Lisa's famous smile is caused by facial muscle contracture and/or synkinesis after Bell's palsy with incomplete nerval regeneration. During pregnancy the incidence of Bell's palsy is increased up to 3.3 times compared to nonpregnant women. The etiology, associated factors as well as various treatment options aiming at the prevention of associated complications and improving recovery of facial nerve function have intensively been evaluated over the past three decades. However, the preferred mode of therapy management, particularly in pregnant women, remains undecided. Corticosteroids may be beneficial if they are applied after the first trimester.