Original research
Continuous combination oral contraceptive pills to eliminate withdrawal bleeding: a randomized trial

An abstract of preliminary findings was presented by poster at The American College of Obstetricians and Gynecologists annual meeting, Chicago, 2001, and final conclusions were presented by poster at The American College of Obstetricians and Gynecologists annual meeting, Los Angeles, 2002.
https://doi.org/10.1016/S0029-7844(03)00014-0Get rights and content

Abstract

Objective

To compare bleeding profiles of a traditional 28-day oral contraceptive pill cycle with continuous administration.

Methods

After a 28-day run-in cycle, women were randomized to either 28-day cycles (21 active pills and a pill-free week) or continuous use of the same 20-μg ethinyl estradiol/100-μg levonorgestrel formulation for 12 study cycles (336 days). The number of bleeding and spotting days were measured by daily diary. A subset underwent cycle 1 (n = 16), and nine (n = 14) pelvic ultrasound and endometrial histology sampling. Blood pressure, weight, hemoglobin, and adverse events were measured at revisit. The sample size with 80% power to detect a 67% reduction in bleeding days required 27 subjects in each arm.

Results

Of the 79 subjects randomized, 28 (70%) of the 28-day cycle and 32 (82%) of the continuous-use subjects completed the entire study (P = .6). With continuous use, 49%, 68%, and 88% of women reported no bleeding during cycles 2, 6, and 12, respectively. Amenorrhea or infrequent bleeding was present in 68% of continuous users during cycles 1–3 and increased to 88% during cycles 10–12. Spotting during cycle days 1–21 increased initially with continuous use but reduced over time, and by 9 months was less than the spotting reported by cyclic users. Adverse events, blood pressure, weight, and hemoglobin findings were similar between groups.

Conclusion

Extension of the 28-day oral contraceptive cycle to continuous use with a low-estrogen dose combination oral birth control pill resulted in significantly fewer bleeding days.

Section snippets

Materials and methods

The study was approved by the local Institutional Review Board, and women were recruited by flyer for contraception without an emphasis on the potential for bleeding reduction. Women were screened by telephone for exclusions before the clinic visit. The study was conducted from January 2000 to September 2001 at a University-affiliated, metropolitan, dedicated research clinic. Subjects were excluded for age less than 18 years or greater than 45 years; standard contraindications to combined OC

Results

Seventy-nine women were enrolled and randomized by August 2000. Data collection was completed by September 2001. Study completion rates by treatment arm and reasons for exclusion and dropout are listed in Figure 1. Table 1 compares the enrollment demographics and baseline characteristics of the two study populations.

There were no statistical differences in age, body mass index, gravidity, parity, partner status, ethnicity, smoking status, education, or prior OC use history between the two

Discussion

Continuous administration of a 20-μg ethinyl estradiol monophasic OC was well tolerated and significantly reduced bleeding compared with cyclic use. Spotting days declined over time with continuous or daily use, and study dropout because of unacceptable bleeding was rare. By study cycle 2 (56 days of daily OC use), 49% of the continuous-use subjects reported no bleeding. This increased to 68% by cycle 6, and by year’s end 88% of continuous-use subjects reported no bleeding (Figure 2). Complete

Acknowledgements

We acknowledge Erika Lease and Suzannah Stout, our study coordinators, for collecting the data and making the research happen.

References (33)

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This investigator-initiated study was funded by Wyeth Laboratories, Philadelphia, Pennsylvania.

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