1. Division of Obstetric Anesthesiology, Stanford University School of Medicine, Stanford, California
2. Department of Obstetrics and Gynecology/Surgical Critical Care Texas Children's Hospital, Baylor College of Medicine, Texas
3. Department of Obstetrics and Gynecology/Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
4. Department of Anesthesiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
5. Department of Anesthesiology and Pain Management, Anesthesiology Institute, Cleveland Clinic, Ohio
6. Division of Obstetrical Anesthesia, University of Arkansas for Medical Sciences, Fayetteville, Arkansas
7. Division of Maternal-Fetal Medicine, University of Arkansas for Medical Sciences, Fayetteville, Arkansas