Oral contraception: patterns of non-compliance. The Coraliance study

To determine the number of times women failed to take their oral contraceptive medication and their behavior in response to a missed pill. Another objective was to determine the potential benefit provided by a continuously administered oral contraceptive compared with an oral contraceptive involving a pill-free interval during a 6-month period.

Healthy women were enrolled in a cohort study; their contraceptive practices were followed by their gynecologists. Data were collected at inclusion using cross-sectional method with retrospective data collection for the previous 6 months and, more specifically, on their previous or their current menstrual cycle. Women on the pill were asked to specify the number of times and precise time at which they missed one or more pills and what they did in response to missing a pill.

A total of 617 gynecologists enrolled and followed 3316 patients from six geographic areas throughout France. The mean age of patients was 30 years. Duration of oral contraceptive use was 8 years. During their previous cycle, 23% of women (n = 737) missed a pill at least once. Among women on the pill involving a treatment-free interval, 42% of instances of missing a pill occurred during the first week following the treatment-free interval. In response to missing a pill, patients read the product information leaflet (39%) or asked someone's advice (28%), mainly their gynecologist (63%) or their family physician (18%). Almost one-third of women did not take any specific measures.

Patients on a discontinuous oral contraceptive regimen tended to miss a pill during the first week of treatment. Prescription of a continuous regimen without a treatment-free interval may improve compliance.