1. Department of Obstetrics and Gynecology, Columbia University Medical Center
2. Biostatistics and Epidemiology Program, CUNY School of Public Health, Hunter College
3. Heilbrunn Department of Population and Family Health, Columbia University
4. Department of Pediatrics, Columbia University Medical Center, New York, NY
5. Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco, CA
6. New York Presbyterian Hospital, New York, NY, USA