The lining of the uterus and cervix might be injured by a variety of oxidation products of Cu in a Cu-IUD, including cuprous ions, dissolved and precipitated cupric ions, and reactive oxygen species such as superoxide radicals, hydrogen peroxide, and hydroxyl radicals. In this study, the human amnious WISH cell line was employed as a model of uterine cells in the presence of copper. The cell viability was decreased by elemental copper, which was alleviated up to 70% by the addition of catalase. The addition of copper oxychloride caused cell death in a dose-dependent manner. Hydroxyl radicals in the presence of copper were determined by the formation of malondialdehyde. Soluble cuprous chloride complexes are formed in the uterus by slowly entering oxygen. The complexes are partly oxidized to insoluble copper oxychloride. which damages the endometrium. Unoxidized cuprous ions migrate to the oxygen-rich cervix and are oxidized to copper oxychloride, causing cervix damage.