Objectives: This study explores how legislators use scientific evidence in making policy on two key reproductive health issues: abortion, and alcohol use in pregnancy. Methods: We conducted semi-structured interviews with state legislators and their aides in three US states that have a mix of policies on abortion and alcohol use in pregnancy. Our questions explored how legislators make decisions on these policies, how they assess the credibility of evidence they encounter, and how they balance evidence with other concerns. Interviews were recorded, transcribed, and coded using Dedooce. Results: We conducted 28 interviews, lasting an average of 33 minutes. 19 participants were Democrats and 9 were Republicans. Preliminary findings suggest that science is only one of many factors influencing policy decisions; partisan politics play a strong role, while personal values and preexisting beliefs are also influential. Motivated reasoning is common, where evidence is judged not by its own merits but by how well it aligns with predetermined policy preferences and beliefs. In the area of substance use on pregnancy, opioid use in pregnancy appears to have higher salience for legislators than alcohol use. In abortion policy, partisan identity appears more influential than any data in shaping a legislator’s policy decisions. Conclusions: Researchers and practitioners hope policies influencing reproductive health will be based on the best available evidence. This work sheds light on how evidence and other influences are weighed by legislators in enacting health policies, and may help researchers and others develop more realistic expectations for translating evidence into policy.