As a result of the complexity of contraceptive behaviour61 and additional factors as simple as forgetting, Canadian's adherence to contraceptive methods is far from perfect. About 9% of Canadians who responded to a study on contraception8,9 indicated that they use no method of contraception, despite the lack of desire to conceive. Adherence problems with chosen methods were also common: 62% of the respondents who identified themselves as current oral contraceptive users reported having missed at least one pill during the 6 months before the survey; 31% of these respondents missed 1 or 2 pills, and 11% missed 6 or more pills during this time.8,9 Similarly, 30% of the respondents who reported using condoms indicated that they did not always use a condom during sexual intercourse in the 6 months before the survey. Perhaps not surprisingly, some 28% of the female respondents reported having experienced an unplanned pregnancy.8,9 On the basis of these findings, it appears that adherence to a contraceptive method and not the choice of method per se may be the more challenging goal for clinical counselling and patient practice. Box 2 presents empirically validated counselling techniques62–64 that may be effective in challenging situations in which patients have particular difficulties adhering to their chosen method of contraception.

Oral contraceptives are highly effective and may be considered, in the absence of contraindications (Box 1), for women seeking a reliable, reversible method of contraception. They also have a number of noncontraceptive benefits that may make them a desirable option.2 Side effects are usually minor and diminish after the first 3 cycles of use.16 Studies have not shown an association between use of a low-dose oral contraceptive (20–35 μg ethinyl estradiol per day) and weight gain22 or mood changes.43 Risks associated with oral contraceptive use include venous thromboembolism (3- to 4-fold increased risk compared with nonuse).17,18 A significant pharmacokinetic interaction between oral contraceptives and antibiotics other than rifampin and griseofulvin has not been found.2