The side effects of birth control depend on the patient and vary by the method being used. For example, the major side effect of an implantable such as Nexplanon is irregular bleeding. The shot (Depo-Provera) can be an appetite stimulant, and some patients can gain weight. It can also remain effective for up to a year after stopping the shot, so it may be harder to get pregnant afterwards. You may also experience irregular bleeding. Side effects of the ring (NuvaRing) include discomfort in placement and irregular bleeding. In addition, some people have trouble with it falling out during intercourse. Side effects of the pill include cramping, nausea, bloating, menstrual headaches, irregular bleeding, and breast tenderness.