1. Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, Texas
2. Division of Neonatal-Perinatal Medicine, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas
3. Division of Obstetric Anesthesia, Department of Anesthesia, University of Texas Southwestern Medical Center, Dallas, Texas
4. Parkland Health and Hospital System, University of Texas Southwestern Medical Center, Dallas, Texas