The present invention relates to compositions comprising selenium (e.g.,organicselenium (e.g., selenized yeast (e.g., SEL-PLEX))) and methods of using thesame (e.g., as atherapeutic and/or prophylactic treatment). For example, the present inventionprovidescompositions comprising selenium (e.g., organic selenium (e.g., selenizedyeast (e.g., SEL-PLEX)))and methods of using the same for treating and/or preventing one or moreconditions(e.g., problems) disorders, and/or diseases related to establishing and/ormaintaining apregnancy. Compositions and methods of the present invention find use in,among otherthings, research and clinical (e.g., preventative and therapeutic)applications.