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Obstet Gynecol. 2001 Nov;98(5 Pt 1):771-8.

Menstrual reduction with extended use of combination oral contraceptive pills: randomized controlled trial.

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  • 1Department of Obstetrics and Gynecology, University of Washington School of Medicine, Seattle, Washington, USA.



To compare a traditional 28-day cycle to an extended 49-day cycle of the 30 microg ethinyl estradiol (E2)/300 microg norgestrel monophasic birth control pill regimen.


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.


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).


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.

[PubMed - indexed for MEDLINE]
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