Jan. 19, 2000 (Minneapolis) -- Oral contraceptives are known to increase the risk of heart problems for women who smoke. New research at the University of North Carolina at Chapel Hill suggests that not all birth control pills are created equal. The difference might be due in part to the specific type of hormones contained in "the pill." The findings were published in the January issue of the medical journal Obstetrics and Gynecology.
While 22 million U.S. women continue to smoke, those who take oral contraceptives, or birth control pills, run a higher risk of premature death than women who are on the pill but do not smoke. The risks are higher for some women than for others.
"[Women] need to be aware of the implications that newer forms of oral contraceptives have for long-term health," study investigator Patricia Straneva tells WebMD. "[This study] provides evidence that we should consider not only the side effects and concerns about [birth control] types and what might be best for women, but also how oral contraceptives might impact their future health."
Researchers found that older, "second generation" oral contraceptives have a higher content of hormones called androgens. Androgens are steroids, such as testosterone. The newer, "third generation" formulations have a lower androgen content.
Young, healthy female smokers and nonsmokers taking two different types of oral contraceptives were studied while at rest and during mental and physical stress. Among smokers, researchers found that their hearts were pumping less blood, yet there was more tension in the blood vessels resisting blood flow. While these findings were not surprising considering the harmful effects of smoking on the heart, women taking the older version of oral contraceptives had the highest blood pressures and blood vessel tension.
"Based on our findings, the type of [hormone] women take should be an important consideration when choosing oral contraceptives, especially among women who continue to smoke," Straneva tells WebMD. "For some women, the newer contraceptives may impart less risk, but that's a choice that ultimately needs to be made between a woman and her doctor."
Straneva says that some physicians continue to prescribe the older forms of oral contraceptives; some do simply because they are comfortable with that choice for their patients.
Straneva cautions that even the newer third-generation oral contraceptives might not be appropriate for all women. She cites one study that suggests these medications might be linked with a higher risk of blood clot formation. Another, more recent investigation, however, indicated that might be true only for women genetically predisposed to clotting. Clearly, more research on newer formulations needs to be done, she says.
The best advice for young women considering oral contraceptives, Straneva says, it to be "an informed consumer. When you're interested in starting an oral contraceptive, educate yourself about what would be best for you. Investigate your options by requesting information from your doctor's office, and go to the library and review women's health guides."
The best advice for smokers, according to Irvin Jones, MD, of the obstetrics-gynecology department at Yale University School of Medicine, is to "quit smoking."