How to tell if my symptoms are side effects of birth control?

Most have none: Most women who take birth control pills have no side effects, but the most common side effect in the first 1-3 months is irregular, unpredictable bleeding that gets better over time. Other possible side effects include breast tenderness, nausea, mood changes, headaches. One way is to see if you feel better when you're on the placebo pills. If so, talk with your dr. There are many bc options.