In 1992, the FDA approved Depo-Provera as an injectable contraceptive for women, used to prevent pregnancy. However, by 2004, the FDA announced that using Depo-Provera could result in irreversible bone density loss, a risk that might increase if the drug is administered over a long period of time. Therefore, the FDA now recommends that women not use Depo-Provera for over two years, and requires that all labeling of the drug contain the necessary warnings about potential bone density loss. Furthermore, Depo-Provera causes a number of potentially serious side effects, including an increased risk of developing breast cancer in patients under the age of 35, and a greater chance of experiencing a blood clot that might move to a patient's lungs and/or brain. Finally, studies have shown women taking Depo-Provera have a risk of developing two sexually-transmitted diseases, i.e. chlamydia and gonorrhea, that is approximately three times the risk of women who are not using hormonal-based birth control methods.