Feasibility of recruitment for an efficacy trial of emergency contraceptive pills

Background: The efficacy of emergency contraceptive pills (ECPs) is currently uncertain. The best way to obtain a robust efficacy estimate would be to conduct a placebo-controlled randomized trial. We aimed to assess the feasibility of identifying women eligible for such a trial. Study Design: We conducted a survey of women aged 18-35 years in five sexually transmitted disease clinics and urgent care centers in Kenya and the United States in 2006. Results: Of 177 women surveyed, only 10 (6%) reported no reasons for exclusion from a potential efficacy trial. Of the rest, 149 (83%) had not recently had sex that conferred a substantial risk of pregnancy. At all sites combined, the rate of identification of potentially eligible women was 0.6 per day of interviewing. Conclusion: A placebo-controlled efficacy trial of ECPs would likely require several thousand participants. Recruitment for such a trial in these types of sites would be prolonged.