Switching the brand of birth control pill used may help deal with side effects.

Side Effects of Birth Control Pills

Some women have side effects when taking birth control pills. If these side effects last for more than three months, talk to your doctor about changing to a brand of birth control pills that contains a different dose of hormones. Don't stop your pills without consulting your doctor and starting a new method of birth control. Side effects may include:

• nausea
• bloating
• headaches
• breast tenderness
• bleeding between your periods
• decreased libido

Very rarely, birth control pills can cause non-cancerous liver tumours. If you experience persistent pain in your abdomen while on birth control pills, you should see your doctor.

Blood Clots and the Risks of Cardiovascular Disease

Birth control pills that contain estrogen can increase your risk of having blood clots. This is a small risk for healthy women. Women who are at increased risk of cardiovascular problems, such as women over 35 who smoke, or women with high blood pressure increase their risk of heart attack or stroke if they also take birth control pills. They are often advised to use another method of birth control. Estrogen-containing birth control pills are not recommended for women who have or have had:

• blood clots
• heart disease
• stroke
• high blood pressure greater than 160/100
• severe migraines
• heart defects

Birth Control Pills and Cancer

There is no evidence that the birth control pill causes cancer. In fact, they have been shown to decrease the risk of getting ovarian or endometrial cancer (cancer of the uterus). There is some evidence that women taking the pill have a slightly increased risk of breast cancer while on the pill (1.4x their risk if they weren't on the pill). However, the risk gradually goes back to normal after stopping the pill so that if it has been more than 10 years since you took birth control pills, your risk is not greater than the risk for a woman who never took birth control pills. Women with breast cancer should not take the pill, since hormones might affect the growth of tumour tissue.

Birth Control Pills and Pregnancy

No studies have shown that taking birth control pills harms a pregnancy, however women should stop taking birth control pills if they learn they are pregnant. Birth control pills do not harm a breast-feeding infant. They are not recommended for breast-feeding women, however, because hormones can reduce milk production.