1. Department of Obstetrics and Gynecology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
2. Department of Obstetrics and Gynecology, Cleveland Clinic, Cleveland, Ohio
3. Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, Michigan
4. Department of Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
5. Leonard Davis Institute of Health Economics, Perelman School of Medicine, Philadelphia, Pennsylvania