Immune cells will be studied from the reproductive tract of women who want to start using one of the following contraceptives: Depo-Provera (DMPA), NET-EN, MPA/E2 (Cyclofem®), the levonorgestrel subdermal implant (Jadelle® ), the etonogestrel subdermal implant (Implanon® or Nexplanon® ) and the copper IUD.