Birth control pills, also known as oral contraceptives, are a reliable way to prevent pregnancy: According to the medical database UpToDate, if used perfectly, the theoretical rate of failure is 0.1%; if used imperfectly, the failure rate is 2 to 3 percent. Oral contraceptives are also used in other conditions, such as having heavy bleeding during a menstrual cycle. However, several side effects, though rare, are potentially fatal. Patients considering the use of birth control pills for any reason should be aware that these side effects may occur.
Stroke
One kind of stroke that a person could experience is called an ischemic stroke, in which the oxygen to the brain is stopped because of a blood clot in a major blood vessel to the brain. For several years, there has been debate about whether birth control pills increase the risk of stroke in women. The fact that older formulations of birth control pills contained much higher levels of estrogen compared to the currently available birth control pills added to the confusion.
A definite conclusion cannot yet be made about this potential link. However, a study published in July, 2000, in the Journal of the American Medical Association reviewed many previously published studies. The authors of the 2000 study concluded that women taking birth control pills--even preparations with a lower dose of estrogen--have a slightly increased risk for stroke.
Because the total number of strokes in women of reproductive age is so low, the actual increased risk translates to a small number. However, a woman considering the use of birth control pills needs to know that this potential side effect could occur.
Cervical Cancer
There appears to be an increase in the risk for developing cervical cancer among women who take birth control pills. Harvard Medical School professor of endorinology Kathryn A. Martin and her colleague, Dr. Pamela Douglas, writing in the medical database UpToDate, suggest that this association has been found in many studies. A significant source of evidence comes from a huge review of data from 24 studies; this review looked at over 16,000 women with cervical cancer and over 35,000 without cervical cancer. The authors of this study, which was published in the journal "Lancet" in 2007, conclude that there is an increased risk of cervical cancer among current birth control user. This risk decreases after birth control pill usage stops. After a decade of being off "the pill," a woman's of cervical cancer comes back down to the same risk as that of women who were never on an oral contraceptive.
Blood Clots
Several studies have concluded that there is an increased risk of potentially deadly blood clot formation among women who take oral contraceptives. A blood clot may start in the leg--this is called deep venous thrombosis--and travel up to the lungs. At this point, the clot is called a pulmonary embolism and can be fatal.
An analysis of over 20 studies was published in 1997 in the journal "Archives of Internal Medicine"; this study concluded that the risk of blood clots in women who take oral contraceptives is elevated. Some studies found only a slightly elevated risk of blood clots. Other studies found that women who take birth control pills have almost 5 times the risk of blood clots compared to women who are not taking these pills.
The overall conclusion drawn by the authors of the 1997 analysis is that the risk is elevated but that since the number of women who get blood clots is very small regardless of birth control use, the association is probably a bit exaggerated. Nonetheless, the possibility of such a side effect is important to know about if a woman is considering the use of birth control pills.
References
- "Journal of the American Medical Association"; Ischemic stroke risk with oral contraceptives: A meta-analysis; L.A. Gillum et. al.; July 2000
- "Lancet"; Cervical cancer and hormonal contraceptives: collaborative reanalysis of individual data for 16,573 women with cervical cancer and 35,509 women without cervical cancer from 24 epidemiological studies; P. Appleby et. al.; November 2007
- "Archives of Internal Medicine"; A reevaluation of the risk for venous thromboembolism with the use of oral contraceptives and hormone replacement therapy; J.D. Douketis et. al.; July 1997
- "UpToDate"; Denise S. Basow; 2010
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