Depo-Provera can cause missed periods. While it is a highly effective method of contraception, pregnancy rates are still estimated at six out of 100 users per year. If you miss your period and wonder if you are pregnant, taking a pregnancy test is the only way to know for sure.  Take a pregnancy test if you experience pregnancy symptoms such as breast tenderness and growth, fatigue, nausea, food aversions, and a frequent need to urinate. If it is positive, call your doctor’s office.