Objective.-The aim was to assess the timing and severity of self-reported headaches in patients utilizing a standard 28-day oral contraceptive (OC) cycle consisting of 21 hormone (estrogen + progestin)-containing pills and 7 placebo pills (ie, 21/7-day cycle) converted to a placebo-free extended OC regimen.Methods.-An open label single-center prospective analysis of headaches recorded daily on a severity scale of 0 to 10, along with the headache item of the Penn Daily Symptom Rating (DSR17) and a weekly modified Migraine Disability Assessment (MIDAS) headache questionnaire, during standard 21/7-day cycles followed by a 168-day extended placebo-free regimen of an OC containing 3 mg of drosperinone and 30 mcg of ethinyl estradiol (DRSP/EE).Results.-Of the 114 patients who began the trial, 111 completed the 21/7-day cycle portion of the study. Based on the headaches scales, there were significant differences in headache severity among the 28 days of the standard 21/7 cycles (P < .001). Greater headache severity occurred on days 25 through 28 during the 7-day placebo interval of the 21/7 cycles (P < .05). Of the 111 patients who completed the 21/7 phase of the study, 102 (92%) completed the 168-day extended placebo-free OC regimen. During the first 28 days of the extended placebo-free regimen, daily headache scores decreased (P < .0001) compared to those of the previous 21 active/7 placebo day cycle. The difference on a daily basis was first detected on extended cycle days 25 through 28 (P < .0001) and persisted throughout the remainder of the 168-day regimen. Subjects were divided into 2 groups (severe and mild) based on the median of the total headache score during the 21/7 OC cycle. The group with higher total headache scores demonstrated a significant (P < .0001) reduction in daily headaches beginning in the first 28-day interval of the extended placebo-free regimen, persisting throughout the entire 168-day extended regimen. In contrast, the group with the lower total headache score remained unchanged (P = .79) throughout the extended regimen. Impact of headaches on work, family, and social functions also improved on the extended placebo-free regimen in 6 of 8 measures (P < .05) assessed by weekly headache questionnaires.Conclusion.-Compared to a 21/7-day OC regimen, a 168-day extended placebo-free regimen of DRSP/EE led to a decrease in headache severity along with improvement in work productivity and involvement in activities. This is a preliminary study and results may not be widely generalizable.Key words: oral contraceptive pills, headaches, hormone withdrawal symptoms, drosperinone Abbreviations: OC oral contraceptives, PMS premenstrual syndrome, PMDD premenstrual dysphoid disorder, DRSP drosperinone, EE ethinyl estradiol, MIDAS migraine disability assessment, DSR daily symptom rating, BMI body mass index, SE standard errors (Headache 2007;47:27-37) From the Scott and White Memorial Hospital-Obstetrics and Gynecology, Temple, TX.