Will women accept randomization in a clinical trial of hormonal contraceptives?

Abstract

Despite the clear scientific merit of randomized clinical trials questions remain regarding whether this study design is sufficiently used in pharmacologic research involving hormonal contraceptives as well as whether women will accept random assignment in such a clinical trial. To evaluate these questions the authors performed a systematic review of published literature in three peer-reviewed journals to assess the study design participant assignment and the type of hormonal contraceptive used. In addition the authors undertook a review of the recruitment experience of a randomized clinical trial of hormonal contraceptives called the Contraceptive Hormone Assessment of Risk Markers study (CHARM). All articles involving the use of hormonal contraceptives in humans were reviewed. The majority of articles (62%) could be classified as observational in study design with the cohort study being the most commonly used type. Furthermore only 18% of studies used random assignment and it was rare (4.8%) to find a clinical trial that randomized participants to groups that used different types of hormonal contraceptive delivery systems (i.e. oral vs. parenteral delivery). During recruitment for the CHARM study 2079 women were contacted by telephone 472 (23%) attended a screening visit and 125 (5%) were considered eligible and were randomly assigned to 1 of 2 different hormonal contraceptive delivery systems (the levonorgestrel implant or an oral contraceptive). The recruitment experience in CHARM was similar to that of other clinical trials in the Memphis Tennessee area. The authors infer that the randomized clinical trial study design is being underused in hormonal contraceptive research even though it seems that women are willing to participate in a randomized clinical trial and to accept randomization to different types of hormonal contraceptive delivery systems. (authors)