Teratogenic risks from exposure to illicit drugs.

Substance use is prevalent in the United States, especially in the reproductive age population. Even though a reduction in substance use may occur during pregnancy, some women may not alter their drug use patterns until at least pregnancy is confirmed. For these reasons, a large number of fetuses are exposed to illicit substances, including during critical stages of organogenesis. Associating illicit drug use with eventual pregnancy outcome is difficult. This article presents issues pertaining to limitations with published investigations about fetal risks and describes the most current information in humans about fetal effects from specific illicit substances.