As U.S. states legalize marijuana and as governmental attention is paid to the “opioid crisis,” state policies pertaining to drug use during pregnancy are increasingly important. Little is known about the scope of state policies targeting drug use during pregnancy, how they have evolved, and how they compare to alcohol use during pregnancy policies.Method: Our 46-year original data set of statutes and regulations in U.S. states covers the entirety of state-level legislation in this policy domain. Data were obtained through original legal research and from the National Institute on Alcohol Abuse and Alcoholism’s Alcohol Policy Information System. Policies were analyzed individually as well as by classification as punitive toward or supportive of women.Results: The number of states with drug use during pregnancy policies has increased from 1 in 1974 to 43 in 2016. Policies started as punitive. By the mid- to late 1980s, supportive policies emerged, and mixed policy environments dominated in the 2000s. Overall, drug/pregnancy policy environments have become less supportive over time. Comparisons of drug laws to alcohol laws show that the policy trajectories started in opposite directions, but by 2016, the results were the same: Punitive policies were more prevalent than supportive policies across states. Moreover, there is a great deal of overlap between drug use during pregnancy policies and alcohol/pregnancy policies.Conclusion: This study breaks new ground. More studies are needed that explore the effects of these policies on alcohol and other drug use by pregnant women and on birth outcomes.