To compare the bleeding profile of a traditional 28-day oral contraceptive (OC) cycle with continuous administration.
Methods and Results
Seventynine women were randomized to a 28-day regimen (21 active pills and a pill-free week) or continuous use of the same low-dose formulation (20 μg ethinyl estradiol/100 μg levonorgestrel) for 12 cycles. Women recorded the number of bleeding and spotting days, and a subset underwent pelvic ultrasound and endometrial biopsy in cycles 1 and 9.
During the first 3 cycles, 68% of continuous users experienced amenorrhea or infrequent bleeding; that rate increased to 88% during the last 3 cycles. Continuous users initially experienced a slight increase in spotting during cycle days 1 through 21, but it diminished over time and ultimately was less than that reported by cyclic users.
Who may be affected by these findings?
Women of reproductive age who wish to reduce monthly bleeding.
The notion that menstruation must occur each month in healthy, nonpregnant women using contraception is increasingly being questioned. One of the main factors contributing to this perception has been the packaging and labeling of OCs to induce monthly withdrawal bleeding.
Endometrium does not ‘build up.’ Monthly menstruation is not critical to OCs’ mechanism of action. Nor does OC-induced amenorrhea lead to harmful “build-up” of the endometrium. Rather, extended OC use results in a thin, atrophic endometrium that is protective against hyperplasia and endometrial cancer.
Continuous use is well tolerated. This study showed continuous use to be well tolerated, with a low drop-out rate and little anxiety about pregnancy. Data also suggested a small improvement in compliance.
Comparable efficacy. Contraceptive efficacy with continuous OC use was comparable to a cyclic regimen. (In some cases, continuous use may even be superior, since follicular development can occur during the pill-free week.) As for safety, continuous users who underwent ultrasound and endometrial biopsy had no abnormal findings. Although long-term safety was not completely addressed in this study—as the authors acknowledge—the cumulative estrogen exposure with a daily 20-μg ethinyl estradiol OC over 1 year is less than that of a cyclic 30-μg formulation.
Other benefits. Many other health benefits occur with extended OC regimens. Besides its convenience, medically induced amenorrhea has been used successfully to treat dysmenorrhea, menorrhagia (particularly in women with anemia or bleeding diatheses), endometriosis-related pain, and menstruation-related headaches. In addition, some special populations, such as female athletes, find amenorrhea particularly beneficial.1
What do women want? A number of studies suggest they don’t necessarily want to menstruate monthly. For example, a Dutch survey found that 65% of women aged 25 to 34 preferred bleeding every 3 months or less and 31% favored no bleeding at all.2 Another trial allowed participants to choose their own OC regimen; the median duration of continuous OC use was 9 weeks (maximum 104 weeks), and the median pill-free interval was 5 days.3
Advising patients. In offering my patients the option of extended OC use, I previously recommended scheduled withdrawal bleeds at 3- to 6-month intervals to avoid spotting. With this new evidence, however, I can offer patients even longer periods of amenorrhea. Moreover, a new 91-day extended OC formulation (Seasonale; Barr Laboratories, Pomona, NY) is under development and should be approved later this year.4
Continuous use of a low-dose monophasic OC preparation for 1 year resulted in fewer bleeding days without a significant increase in overall spotting, compared with cyclic use of the same preparation. We can use this evidence to counsel patients about the benefits of continuous OC use and help them achieve menstrual “nirvana.”5