The mask of pregnancy, also called the melasma gravidarum, is a condition that can occur during pregnancy in which dark patches appear on the face. The patches are usually symmetrical and can be found on the forehead, cheeks, nose and upper lip. They are caused by an increase in melanin production and typically appear in the second or third trimester. While they will usually resolve after pregnancy, some women may experience them for several months or even years afterwards. Treatment options include topical creams and laser therapy.