In its efforts to protect the health of unborn children, the government is increasingly attempting to regulate pregnant women's conduct. As with other policies affecting pregnant women's autonomy, these policies have constitutional overtones. In Ferguson v. City of Charleston (2001), the Supreme Court struck down a South Carolina hospital's policy of testing pregnant women for cocaine and turning positive results over to law enforcement for prosecution. This article discusses the basis of the decision and its legal and behavioral implications. Although the decision came down on the side of pregnant women's rights, it left unresolved the issue of whether a similar policy could be constructed that would pass constitutional muster. The article concludes with a consideration of the likely effects of, and alternatives to, such a policy.