It is believed that the greater production of sex hormones during pregnancy cause changes that affect the hearing system, although their specific mechanisms are still under investigation. Physiological changes occur during pregnancy such as the non-pathologic drop of hearing thresholds for low frequencies and diminished hearing tolerance to intense sounds, both of which return to their basal range in the post-partum. Certain diseases, like sudden hearing loss, Ménière´s Disease and otosclerosis can appear for the first time or alter their course during pregnancy. A brief bibliographic revision is made regarding the physiological and pathological hearing changes that occur during pregnancy.