1 Division of Maternal-Fetal Medicine, Women & Infants Hospital of Rhode Island, Alpert Medical School of Brown University, Providence, RI.
2 Department of Obstetrics and Gynecology, New York Medical College, Valhalla, NY.
3 Division of Maternal-Fetal Medicine, Women & Infants Hospital of Rhode Island, Alpert Medical School of Brown University; Department of Health Services, Policy and Practice, Brown University School of Public Health, Providence, RI.