Cande V Ananth1, Justin S Brandt2, Anthony M Vintzileos3. 1. Division of Epidemiology and BiostatisticsDepartment of Obstetrics, Gynecology, and Reproductive Sciences, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ; Environmental and Occupational Health Sciences Institute, Rutgers Robert Wood Johnson Medical School, Piscataway, NJ. Electronic address: ananthcv@rwjms.rutgers.edu. 2. Division of Maternal-Fetal MedicineDepartment of Obstetrics, Gynecology, and Reproductive Sciences, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ. 3. Department of Obstetrics and Gynecology, NYU Winthrop Hospital, NYU Long Island School of Medicine, Mineola, NY.