Molly R. Siegel, MD, Grace K. Mahowald, MD PhD, Sacha N. Uljon, MD PhD, Kaitlyn James, PhD, Lisa Leffert, MD, Mackenzie W. Sullivan, MD, Susan J. Hernandez, CNM, Jessica R. Gray, MD, Davida M. Schiff, MD, Sarah N. Bernstein, MD Fentanyl in the Labor Epidural Impacts the Results of Intrapartum and Postpartum Maternal and Neonatal Toxicology Tests American Journal of Obstetrics and Gynecology Nov 2022