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Am Fam Physician. 2006;73(5):803-804

Clinical Question

Are continuous and extended-cycle combined contraceptives safe and effective?

Evidence-Based Answer

Evidence shows no difference in safety or effectiveness between cyclic and continuous or extended-cycle combined contraceptives. There are fewer menstrual symptoms with extended-cycle contraceptives. Patients’ satisfaction and adherence is similar for all types.

Practice Pointers

American women in the 21st century experience earlier menarche, have fewer babies, breastfeed for shorter periods, and live longer than women in past centuries, and therefore they have many more episodes of bleeding over their lifetimes. Bleeding with contraceptives is caused by pill withdrawal rather than endometrial buildup. There is no biologic reason why monthly cycles are necessary. Because many women prefer fewer days of vaginal bleeding per year, continuous and extended-cycle oral contraceptives have been developed.

To assess the safety and effectiveness of combined oral contraceptives with longer cycle lengths, Edelman and colleagues reviewed the literature for randomized controlled trials comparing 28-day cyclical contraceptives (21 active pills, seven placebos) with continuous combined contraceptives. They found six studies comparing 28-day cycles of combined oral contraceptives with cycles ranging from 49 to 365 days. There was no difference between the regular and extended cycles in satisfaction, adherence, pregnancy rates, or safety. Patients taking continuous oral contraceptives had four to 14 fewer days of bleeding per trimester. In the two studies that included a sonogram or endometrial biopsy, no evidence of endometrial hyperplasia was found after nine cycles.

Although combined oral contraceptive pills also are used to treat conditions such as acne and dysmenorrhea,1,2 there have been no studies on the use of continuous combined oral contraceptives for purposes other than the prevention of pregnancy. Limited data in this review suggest that women taking continuous dosing have fewer headaches and less genital irritation, fatigue, bloating, and menstrual pain.

These are summaries of reviews from the Cochrane Library.

This series is coordinated by Corey D. Fogleman, MD, assistant medical editor.

A collection of Cochrane for Clinicians published in AFP is available at

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