Continuous compared with cyclic oral contraceptives for the treatment of primary dysmenorrhea: a randomized controlled trial.

OBJECTIVE To estimate whether continuous oral contraceptive pills (OCPs) will result in more pain relief in primary dysmenorrhea patients than cyclic OCPs, which induce withdrawal bleeding with associated pain and symptoms. METHODS We conducted a double-blind, randomized, controlled trial comparing continuous to a cyclic 21-7 OCP regimen (gestodene 0.075 mg and ethinyl estradiol 20 microgram) for 6 months in 38 primary dysmenorrhea patients. The primary outcome was the difference in subjective perception of pain as measured by the visual analog scale over a period of 6 months. RESULTS Twenty-nine patients completed the study. In both groups, pain reduction measured by visual analog scale declined over time and was significant at 6 months compared with baseline, with no difference between groups. Continuous regimen was superior to cyclic regimen after 1 month (mean difference -27.3, 95% confidence interval [CI] -40.5 to -14.2; P<.001) and 3 months (mean difference -17.8, 95% CI -33.4 to -2.1; P=.03) of treatment. Secondary outcomes noted no difference between groups in terms of menstrual distress as measured by the Moos Menstrual Distress Questionnaire. After 6 months, there was an increase in weight and a decrease in systolic blood pressure in the continuous group compared with the cyclic group. CONCLUSION Both regimens of OCPs are effective in the treatment of primary dysmenorrhea. Continuous OCPs outperform cyclic OCPs in the short term, but this difference is lost after 6 months. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, www.clinicaltrials.gov, NCT00517556. LEVEL OF EVIDENCE I.