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)
PIP: To address the issues of poor oral contraceptive (OC) compliance and early OC discontinuation, OC use was analyzed in a convenience sample of 6676 women between the ages of 16 and 30 from Denmark, France, Italy, Portugal, and the United Kingdom, obtained from the Wyeth-Ayerst Contraceptive survey conducted in 1993. Logistic regression was used to examine the independent effect of each factor. 81% of the women used their OCs consistently. User characteristics accounted for inconsistent use. Poor compliance was associated with a lack of established routine for pill-taking and failure to read and understand written materials that came with the OC package. Those who understood little or none of the instructions were 2.4 times more likely to be among women who missed 2 or more pills per cycle. Other factors for inconsistent use included 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 such as breakthrough bleeding and amenorrhea (RR = 1.3), and breast tenderness (RR = 1.2). Women who were inconsistent OC users, missing 1 or more pills per cycle, were 2.6 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 in the first 3 months (RR = 1.9), breast tenderness (RR = 1.8), mood changes (RR = 1.8), hair growth (RR = 1.7), and weight gain (RR = 1.4). Multiple side effects substantially increased the likelihood of discontinuation, with a single side effect increasing the risk by 50%, 2 by 220%, and 3 by 320%. Improved compliance can be facilitated if providers emphasize the need to continue to take OCs reliably even if side effects do occur.