1. Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
2. Department of Obstetrics and Gynecology, University of California-San Francisco, San Francisco, CA, USA
3. Department of Anesthesiology, Columbia University, New York, NY, USA
4. Obstetrics & Gynecology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
5. Philadelphia Maternal Congenital Heart Center, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
6. Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, New York, NY, USA