In fact, most women experience lighter, less painful, and more regular menstrual periods. However, women may experience some mild side effects with the pill, mostly due to the estrogen it contains. These include breast tenderness, nausea, weight gain or loss, and spotting between periods. All of these may be temporary or mild, and changing the type of pill used may alleviate the particular symptom. One should also be aware of the risks associated with the combination pill, including an increased risk of angina, heart attack, blood clots in the legs or lungs, and stroke.
Liver tumors are rare, but can occur.
Birth control pills can also elevate blood pressure, though it usually returns to normal when pill use is discontinued. Women who have cardiovascular problems, liver problems, or a history of breast cancer, headaches, or migraines should generally avoid the pill. Other factors that may increase the risks associated with the pill are high blood pressure, diabetes, high cholesterol, and smoking cigarettes. Women over 35 who smoke should choose a different form of birth control. The mini-pill tends to have fewer side effects, and may be appropriate for those who can't take estrogen.