Use and misuse of oral contraceptives: risk indicators for poor pill taking and discontinuation.

The contraceptive efficacy of oral contraceptives (OCs) depends on their proper and continued use, particularly with lower estrogen preparations. However, few studies have examined why women miss pills or discontinue OCs, and those that do tend to be small and to focus on adolescents. To address the issues of poor OC compliance and early OC discontinuation, we analyzed OC use in a convenience sample of 6,676 women between the ages of 16 and 30 from Denmark, France, Italy, Portugal, and the United Kingdom. Logistic regression was used to examine the independent effect of each factor. Poor compliance was associated with a lack of established routine for pill-taking (relative risk [RR] = 3.3), failure to read and understand written materials that came with the OC package (RR = 2.2), not receiving adequate information or help about OCs from their health care provider (RR = 1.5), and occurrence of certain side effects, including hirsutism (RR = 2.1), nausea (RR = 1.4), bleeding irregularities (RR = 1.3), and breast tenderness (RR = 1.2). Women who were inconsistent OC users, missing one or more pills per cycle, were almost three times as likely to experience an unintended pregnancy while using OCs than were women who took their OCs consistently. Factors that predicted early discontinuation (women who wished to continue contraceptive protection but discontinued OC use) were primarily side effects, including nausea (RR = 2.1), bleeding (RR = 1.9), breast tenderness (RR = 1.8), mood changes (RR = 1.8), and weight gain (RR = 1.4).(ABSTRACT TRUNCATED AT 250 WORDS)