Background: Nationally opioid prescribing for chronic non-cancer pain has increased significantly over the last 20 years. Recently published evidence suggests that 20% to 40% of women received opioid prescriptions of varying doses and durations during pregnancy, which may cause increased risks of harm to mother and fetus. The purpose of this retrospective observational study was to determine the prevalence of opioid prescribing three months before pregnancy, each trimester of pregnancy, and three months postpartum, as well as the secular utilization trend over an eight-year period among member-patients at HealthPartners Medical Group (HPMG). Methods: All pregnant member-patients of HPMG who delivered a live birth between 2006-2014 and had continuous pharmacy benefits beginning three months prior to their estimated pregnancy start through three months postpartum were included. Demographic, clinical, pharmaceutical, and provider variables of interest were identified and described. Significant opioid prescribing during pregnancy was defined as more than five days’ supply prescribed in any three-month period, excluding the two-week postpartum period. Time trends for 2006-2014 were examined using linear regression. Results: Of 11,565 pregnancies during the study period, significant opioid prescribing during three months before, during pregnancy, or three months postpartum periods were observed in 862 (7.5%) pregnancies (816 unique women). A total of 454 (3.9%) pregnant women received significant opioid prescriptions during one or more trimesters of their pregnancy. From 2006 to 2014, the rate of significant opioid prescribing during each trimester of pregnancy and three months before and after pregnancy decreased -0.2% per year. Conclusion: Significant opioid prescribing during the three trimesters of pregnancy and three months before and after pregnancy for member-patients of HPMG was significantly lower than reported studies from other populations and locations across the U.S. over the last 15 years. Furthermore, significant opioid prescribing was trending downward slightly over time, rather than rising as reported elsewhere. Explanatory factors for these findings should be explored.