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Randomized Controlled Trial
. 2009 Dec;114(6):1205-1212.
doi: 10.1097/AOG.0b013e3181beab47.

Cycle control with a 21-day compared with a 24-day oral contraceptive pill: a randomized controlled trial

Andrew M Kaunitz  1 , Ronald T Burkman, Alan C Fisher, Katherine D LaGuardia
Affiliations
Randomized Controlled Trial

Cycle control with a 21-day compared with a 24-day oral contraceptive pill: a randomized controlled trial

Andrew M Kaunitz et al. Obstet Gynecol. 2009 Dec.

Abstract

Objective: To compare bleeding patterns between a 21/7-day triphasic norgestimate/ethinyl estradiol (E2) 25-microgram oral contraceptive pill (OCP) and a 24/4-day drospirenone/ethinyl E2 20-microgram OCP.

Methods: In a three-cycle, open-label, multicenter study, healthy, sexually active women were assigned randomly to a 21/7-day (norgestimate/ethinyl E2) or 24/4-day (drospirenone/ethinyl E2) OCP regimen. Randomization was stratified to assure a balanced distribution between regimens for "fresh starts" and "switchers." Bleeding data were collected daily using an interactive voice-response system. Bleeding was defined according to the 2007 U.S. Food and Drug Administration's Reproductive Health Drug Advisory Committee-endorsed criteria.

Results: Across the three cycles, the 21/7-day OCP group (n=165) reported fewer unscheduled bleeding days than did the 24/4-day OCP group (n=167) (mean 4.6 compared with 6.1 days, P=.003). Women using the 21/7-day OCP had significantly fewer episodes of unscheduled bleeding than did those using the 24/4-day OCP (mean 1.47 compared with 2.01, P=.001). Moreover, women using the 21/7-day OCP had a significantly lower absence of scheduled bleeding at each cycle (P<.001). Both regimens were well-tolerated.

Conclusion: A 21-day norgestimate/ethinyl E2 25-microgram regimen results in less unscheduled bleeding and more scheduled bleeding than does a 24-day drospirenone/ethinyl E2 20-microgram regimen.

Clinical trial registration: ClinicalTrials.gov, www.ClinicalTrials.gov, NCT00745901.

Level of evidence: I.

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References

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    1. Sabatini R, Cagiano R. Comparison profiles of cycle control, side effects and sexual satisfaction of three hormonal contraceptives. Contraception 2006;74:220–3.

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