MONTHLY WOMEN’S HEALTH RESEARCH REVIEW

RESEARCH | Safety, Efficacy of Oral Contraceptive That Incorporates Estrogen During Traditional Placebo Week Examined
[July 31, 2008]

Summary of “Efficacy and Safety of a 28-Day Oral Contraceptive With 7 Days of Low-Dose Estrogen in Place of Placebo,” Poindexter et al., Contraception, August 2008.

Oral contraceptives with a modified hormone-free interval have several potential advantages over oral contraceptives that follow the standard regimen of 21 active pills followed by seven hormone-free placebo pills. Barr Pharmaceuticals’ oral contraceptive Mircette contains 150 micrograms of desogestrel and 20 micrograms of ethinyl estradiol taken for 21 consecutive days, followed by two days of a placebo and five days of 10 micrograms of ethinyl estradiol alone. Mircette was the first oral contraceptive marketed in the U.S. that modified the traditional seven-day hormone-free interval by including low-dose estrogen during the placebo period.

Methods and Findings

Alfred Poindexter of the department of obstetrics and gynecology at Baylor College of Medicine and colleagues examined the safety and efficacy of Mircette. The researchers studied 1,347 sexually active women ages 18 to 45 at 93 sites in the U.S. between August 2006 and July 2007. About 68% of the women were white, 19% were black and 9% were Hispanic. The median weight of the participants was 153 pounds and the median age was 27.4 years. About one-fifth of the participants smoked and about half previously used oral contraceptives.

The women agreed to use Mircette as their primary method of contraception for six cycles. Participants received a complete physical exam, including pelvic exam and Pap test and provided informed consent prior to enrolling in the study. The participants were monitored at follow-up visits during cycles one, three and six and, when possible, about four weeks after taking the final dose of the oral contraceptive. The women also were asked to keep a daily paper diary in which they recorded use of the study medication, occurrence of bleeding and/or spotting, use of additional forms of contraception and use of any concomitant medications.