Oral contraception noncompliance: the extent of the problem.

Compliance has been defined as the extent to which a patient's behavior coincides with the clinical prescription. The lowest expected failure rate of oral contraceptive (OC) use has been suggested to be 0.1%; however, in typical users, the failure rate varies by age, race, and marital status. In some populations in the United States (eg, unmarried black adolescents), the failure rate is 18%; rates that factor in the occurrence of abortions suggest an overall failure rate of 6.2% during the first year of use. If the annual failure rate of 6.2% is assumed, long-term failure rates rapidly approach 25% to 50% (ie, the proportion of users who will experience an unintended pregnancy) over 10 years of use. The gap between the lowest expected failure rate and the failure rates seen in typical users is related in large part to problems of compliance. Compliance with OC use includes both correct daily use and continuing use. Factors that contribute to OC discontinuation include the experience of side effects, fears and misinformation about OC side effects fueled by negative media reports, and intermittent use. There are relatively few data regarding the issue of missed pills and correct use, but studies suggest that adolescents may miss an average of 3 pills a month, and at least 20% to 30% of individuals miss a pill every month. Patients may have difficulty in the transition from one packet of pills to the next, and missed pills that extend the hormone-free interval may contribute to the failure rate.(ABSTRACT TRUNCATED AT 250 WORDS)