For a 36-year-old woman who smokes one pack of cigarettes a day, which birth control method is most appropriate?

The progestin-only "mini-pill" is the most appropriate birth control method for a 36-year-old woman who smokes one pack of cigarettes a day due to its safety profile concerning cardiovascular risks.

Women who smoke, especially those over the age of 35, face increased risks of thromboembolism when using hormonal contraceptives that contain estrogen, such as the combination oral contraceptive pill or the transdermal contraceptive patch. These methods can elevate the risk of blood clots—which is a significant concern in smokers due to the heightened risk factors associated with smoking and oral estrogen.

In contrast, the progestin-only pill does not contain estrogen and thus does not share the same risks of thromboembolic events. It is a suitable alternative for women who have other risk factors such as smoking, placing them at a lower risk for complications and providing effective contraception. The vaginal contraceptive ring also contains estrogen, which could exacerbate risks for this patient population.

Given these considerations, using the progestin-only "mini-pill" offers an effective means of contraception while minimizing health risks associated with her smoking habit and age.