Objective: To evaluate copper intrauterine devices (IUDs) and levonorgestrel-releasing intrauterine systems (LNG-IUS) as protective factors against cervical cancer and precursor lesions. Methods: Case-control study, whose sample will be selected from women who have had at least one cytological examination for cervical cancer screening performed at the Family Planning Clinic of the Department of Obstetrics and Gynecology, School of Medical Sciences, State University of Campinas (UNICAMP). We estimate that there will be 36,469 cases treated between 1999 and 2017. All women who have had a cytological examination will be considered cases. We estimate that we will have 36,469 cases seen between 1999 and 2017. All women who had an abnormal cytological examination (cervical cancer or precursor lesions) during follow-up at the outpatient clinic will be considered as cases. This universe is estimated to be approximately 1,000 women based on the information system of the Cytopathology Laboratory of CAISM, UNICAMP. Women selected at the same outpatient clinic but with normal cytological tests throughout the follow-up period will be considered as controls. The total number of controls will be the same as the total number of cases. For pairing cases and controls, the criterion adopted will be the year of the cytological examination with abnormal results (cases), i.e., for each abnormal cytological examination, a woman will be selected with a normal cytological examination performed in the same year, immediately preceding and following the case.