What are the long-term effects of birth control pills?

Originally Published: July 29, 2005
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I have searched your archives but have not found an answer to my question, and I was wondering if maybe you could help me out. I was wondering about the effects of taking birth control pills for an extended period of time and how long one can safely take them. Any information/advice you could give me would be greatly appreciated.

-Looking for answers

Dear Looking for answers,

It's common to have concerns and misconceptions about taking oral contraceptives (OCs) for long periods of time. However, studies conducted over the last 40 years provide evidence of many advantages and health benefits of OC use.

OCs have been more thoroughly studied than any other medication in history and have been found to be safe for the majority of women. The safe use of OCs depends upon careful evaluation and selection of patients by health care providers. For most healthy, nonsmoking women, prolonged use of OCs does not appear to have adverse effects, and as a result, are an effective birth control method for them, and safe to use throughout their reproductive lives. However, some women, such as smokers, may be at increased risk for health-related problems, and therefore are not good candidates for using OCs.

There is no medical indication for "taking a break" from OCs. In other words, it is not medically necessary. In fact, if stopping OCs puts a woman at risk for pregnancy, it is not recommended.

OCs also have no adverse effect on future fertility, do not defer menopause, nor do they hasten menopause's onset. Most women ovulate within a couple of weeks of discontinuing OCs. Less than 3 percent of women have a delay in the return to fertility. OCs do not correct any underlying ovarian dysfunction, however, so women can expect to return to the menstrual pattern that existed prior to OC use.

Women who have used OCs have a 40 percent reduction in the risk of developing endometrial and ovarian cancer, when compared to women who have never used OCs. In fact, women who have used OCs for 10 years or longer have an 80 percent reduction in risk. This protective effect lasts for 20 years after discontinuing OCs.

Cervical cancer is caused by the sexually transmitted human papilloma virus (HPV). OC users have a higher risk of developing cervical cancer if exposed to this virus since they are less likely to use condoms. In addition, OCs cause eversion of the cervical opening, exposing vulnerable cells to invasion by HPV.

Meta-analysis of over 50 studies provides evidence that OC use does not increase the risk of developing breast cancer. OC use by women with a family history of breast cancer does not increase the risk of developing breast cancer. Current users of OCs are slightly more likely to be diagnosed with breast cancer than nonusers, perhaps due to the increased likelihood that OC users have additional medical visits, which would include breast exams. It is possible that an existing tumor may be stimulated by OCs; however, length of OC use does not increase the risk. Many experts have concluded that OCs have little or no effect on breast cancer risk.

OCs do not significantly increase the risk of heart attack or stroke in healthy, nonsmokers. In most women, combined oral contraceptives do not have a significant impact on the coagulation system. There is an increased risk of venous thromboembolism (blood clot) among OC users usually because of genetics. Other factors that increase a women's risk for blood clots are obesity, prolonged immobilization, and previous vein problems. The risk for developing blood clots is highest during the first two years of OC use and declines over time. This effect is reversible.

The many non-contraceptive benefits of oral contraceptive pills, as well as their safety profile, make them a valuable birth control option for the vast majority of women. If you are concerned about what all this means for you, you can talk with your women's health care provider.