Several ways exist to begin taking oral contraceptives; a woman who does so should carefully follow the instructions of her health-care practitioner. Unlike other oral contraceptives that are taken in 28-day cycles, Seasonale is taken daily for 3 months, followed by 7 days of inactive tablets before taking it for another 3 months. Some med­ications reduce the effectiveness of oral contraceptives; these are listed in ■ Table 10.4.

Forgetting to take one or more pills sharply reduces the effectiveness of oral contra­ceptives, as does taking the pill at a different time each day. Missing one or more pills can lower hormone levels and allow ovulation to occur. A significant number of women do forget to take the pill each day. However, women underestimate how often they forget their pills. A study that relied on electronic tracking of the time and date women took pills from the container, rather than on user self-report, found that up to 50% of users missed three or more pills per cycle, greatly reducing the contraceptive effectiveness of the method (Potter et al., 1996). To help prevent missing pills, a woman can use a pill case with a built – in clock and alarm to alert her at the same time each day if she has not taken her pill.

If you are using oral contraceptives and you miss a pill, you should take the missed pill as soon as you remember and then take your next pill at the regular time. If you forget more than one pill, it is best to consult your health-care practitioner. You should also use a backup method, such as contraceptive foam or condoms, for the remainder of your cycle. •

■ TABLE 10.4 Medications That Reduce Oral Contraceptive Effectiveness

Some medications can reduce the effectiveness of birth control pills. Tell every physician who gives you medication that you are taking oral contraceptives. Use a backup method, such as foam or condoms, when you use any of the following

medications or herbal remedies.




rifampin (for tuberculosis)


phenylbutazone (for arthritis)


St. John’s Wort

SOURCES: Markowitz et al. (2003) and Zlidar (2000).

Deciding to discontinue using the pill requires thoughtful planning to prevent preg­nancy. About 61% of unintended pregnancies are attributable to women discontinuing the pill and adopting a less effective method or using no method (Dempsey et al., 2011).