The purpose of this study is to identify locations in the United States where community exposure to the phenoxy herbicide 2, 4, 5 can be examined in relation to the risk of spontaneous abortion and other adverse pregnancy outcomes. Prior ecologic studies evaluating the reproductive consequences of exposure to 2, 4, 5-T have produced equivocal results. In this report, the authors consider what research strategies and what populations may be used to generate evidence that can be more readily interpreted. Issues relating to the nature of the exposure (e.g. seasonal use, unknown dose level and fate in the environment) and to ascertainment of spontaneous abortions (e.g., memory bias, variability in medical service use) are discussed. Two candidate study areas are investigated. Research approaches suitable to each site are set out and assessed for their potential to provide a powerful, valid test of the relationship of 2, 4, 5-T use to spontaneous abortion.