Obstetrical randomized controlled trials: individuals screened, approached, and enrolled.

Background: The use of randomized clinical trials (RCTs) is predicated on the idea that the study group is representative of the overall clinical population; however, recent studies have suggested that this may not be the case in obstetrics. The generalizability of several seminal obstetrical RCTs, including the A Randomized Trial of Induction Versus Expectant Management trial, has been questioned because of the high ratio of assessed-to-enrolled individuals. Although difficulty in recruitment for obstetrical RCTs is known, it has been postulated that this high ratio increases the likelihood of the study population not being truly representative.