Objectives: Oral hormonal contraception is an effective contraceptive method as long as regular daily intake is maintained. However, a daily routine is a constraint for many women and can lead to missed pills, pill discontinuation and/or unintended pregnancy. This article describes the frequency of inconsistent use, the consequences, the risk factors and the possible solutions.
Methods: The article comprises a narrative review of the literature.
Results: Forgetting one to three pills per cycle is a frequent problem among 15-51% of users, generally adolescents. The reasons for this are age, inability to establish a routine, pill unavailability, side effects, loss of motivation and lack of involvement in the initial decision to use oral contraceptives. The consequences are 'escape ovulations' and, possibly, unintended pregnancy. Solutions are either to use a long-acting method or, for women who prefer to take oral contraceptives, use a continuous or long-cycle regimen to reduce the risks of follicular development and thus the likelihood of ovulation and unintended pregnancy. A progestogen with a long half-life can increase ovarian suppression.
Conclusions: For women deciding to use oral contraceptives, a shortened or eliminated hormone-free interval and a progestogen with a long half-life may be an option to reduce the negative consequences of missed oral contraceptive pills.
Keywords: Compliance; efficacy; half-life; hormone-free interval; missed pill; nomegestrol acetate; non-compliance; progestogen; regimen.