All health-care providers need to understand the effects of alcohol, nicotine, and other drugs on the mother and developing fetus and the ways to promote abstinence or at least a decrease in use. The use of these substances may produce chronic and/or catastrophic effects that fence the pregnant woman into contact with the health-care system. Such contact can produce a healthier outcome for both the mother and fetus if it includes identification of substance use and intervention to promote abstinence. In this article, the author describes the consequences of prenatal substance use for the mother and fetus, identifies techniques used to screen and assess prenatal substance use, and explains strategies used to intervene in prenatal substance use