139 ISSN 2041-6792 10.4155/CLI.11.178 © 2012 Future Science Ltd Clinical Trial Perspective Clin. Invest. (2012) 2(2), 139–146 Pregnant women and their fetuses deserve timely access to safe, effective, evidence-based care. To this end, pregnant women should be included in clinical trials of drugs and vaccines, except when there is a compelling scientiic or ethical reason not to do so. This article examines the beneits and limitations of two different starting points for research involving pregnant women. The irst option would have stand-alone Phase I trials for pregnant women initiated at the same time as Phase III trials in the general population. The second option would have Phase I trials for pregnant women embedded into late Phase II or Phase III trials, with enhanced monitoring for pregnant women, similar to that done in a stand-alone Phase I trial. Keywords: clinical trials • fetuses • inclusion/exclusion criteria • pregnant women • research ethics • trial design “If we consider the availability of a drug proved to be safe and effective through the devices of modern clinical pharmacology and clinical trials a benefit, then it is unjust to deprive classes of persons, such as children and pregnant women, of this benefit” [1] . More than a decade ago, Emanuel et al. asked and answered the question: “what makes a clinical trial ethical?” [2] . They identified seven ethical requirements, one of which was fair subject (participant) selection – that is, fair inclusion/exclusion criteria, as well as fair recruitment and enrollment practices. This ethical requirement, founded on the principle of justice, “holds that particular individuals, groups or communities should neither bear an unfair share of the direct burdens of participating in research, nor should they be unfairly excluded from the potential benefits of research partici- pation” [101] . In the first instance, the ethical concern is with exploitation (especially the exploitation of vulnerable persons). In the second instance, the ethical concern is with equity. In recent years, with the notable exception of clinical research in developing countries, there has been considerable progress in minimizing the risk of exploitation due to inappropriate inclusion in clinical trials. In part, this is due to the fact that no one seriously disputes the claim that it is wrong to exploit others. Regrettably, there has not been similar progress with respect to the problem of inappropriate exclusion from trial participation. In part, this is because many firmly believe (on beneficient or paternalistic grounds) that it is wrong to include certain classes of persons in clinical trials and thereby to expose them to the potential harms of trial participation. This entrenched belief explains, in part, why the argument for appropriate inclusion in clinical trials has had to be repeated time and again for different classes of persons, be they children [1,3,4] , women [5–7,102] or pregnant women [8–12] . It is now widely accepted – in principle, if not always in practice – by researchers, research sponsors, research ethics committees and research regulators, that research involving children and research involving women benefits children and women, respectively. This is not yet the case for research involving pregnant women, but we expect that it will soon be so, given the validity and weight of the arguments in support of such research. When this day comes, a number of practical ethical issues Research involving pregnant women: trials and tribulations Françoise Baylis* 1 & Scott A Halperin 2 1 Novel Tech Ethics, Faculty of Medicine, Dalhousie University, 1379 Seymour Street, Halifax, Nova Scotia B3H 4R2, Canada 2 Canadian Center for Vaccinology, Departments of Pediatrics & Microbiology & Immunology, Dalhousie University & the IWK Health Centre, 5850/5980 University Avenue, Halifax, Nova Scotia B3K 6R8, Canada *Author for correspondence: Tel.: +1 902 494 2873 Fax: +1 902 494 2924 E-mail: francoise.baylis@dal.ca