OBJECTIVE: To compare a traditional 28‐day cycle to an extended 49‐day cycle of the 30 μg ethinyl estradiol (E2)/300 μg norgestrel monophasic birth control pill regimen.
METHODS: Ninety subjects randomized to either 28‐day cycles with 21 active pills or 49‐day cycles with 42 active pills for a prospective open label trial over four 84‐day reference periods or trimesters. Bleeding, pill taking, and symptom diaries were completed. The sample size with 80% power to detect a 40% reduction in bleeding days required 24 subjects in each arm.
RESULTS: Of the 90 women, 24 subjects (54.5%) on the 28‐day cycle and 29 (63%) on the 49‐day cycle completed the entire study (P = .41). There were no statistically significant differences between the two groups in demographics or continuation rates. There was a significant reduction in bleeding days in the experimental arm beginning in the first trimester (28‐day = 10.9, 49‐day = 6.4 mean days of bleeding, P < .001) and continuing to the fourth trimester (28‐day = 11.3, 49‐day = 5.8 mean days, P = .005). The number of spotting days was similar between both schedules in the first trimester (28‐day = 4.8, 49‐day = 3.7 mean days, P = .24) and continued into the fourth trimester (28‐day = 3.4, 49‐day = 2.9 mean days, P = .30). Annual expenditure for hygiene products was significantly less for extended use subjects (28‐day = $41.45, 49‐day = $17.54 spent, P < .001).
CONCLUSION: Extension of the 28‐day oral contraceptive (OC) cycle to a 49‐day cycle resulted in fewer bleeding days and no increase in mean spotting days or bleeding episodes.
Extension of a monophasic oral contraceptive regimen from 28‐day to 49‐day cycles significantly decreases bleeding and hygiene product use without increased spotting.
Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, Washington.
Address reprint requests to: Leslie Miller, MD, 325 Ninth Ave, Seattle, WA 98104–2499; E‐mail: firstname.lastname@example.org.
Parke‐Davis Women's Healthcare Research Award supported by The American College of Obstetricians and Gynecologists, 1997.
Study medication supplied by Wyeth‐Ayerst Laboratories, Philadelphia, Pennsylvania.
The authors thank Elizabeth Pulos for her thoughtful and careful statistical advice and support.
Financial Disclosure: Author Miller received financial assistance and research support from Wyeth‐Ayerst Laboratories and is a member of the company's speakers bureau.
Received February 16, 2001. Received in revised form June 11, 2001. Accepted July 16, 2001.