Evidence-based obstetrics and gynecology / edited by Errol R. Norwitz, MD, PhD, MBA, Louis E. Phaneuf Professor of Obstetrics & Gynecology Tufts University School of Medicine Chief Scientific Officer Chair, Department of Obstertrics & Gynecology Tufts Medical Center, Boston, MA, USA, Carolyn M. Zelop, MD, Director of Ultrasound and Perinatal Research Division of MFM and Department of Obstetrics and Gynecolgy, The Valley Hospital, Ridgewood, NJ, USA, Clininical Professor of Obstertrics and Gynecolgy, NYU School of Medicine, New York, NY, USA, David A. Miller, MD, Division of Maternal-Fetal Medicine Department of Obstertrics and Gynecology Keck School of Medicine University of Southern California, Los Angeles, CA, USA, David Keefe, MD, Stanley H. Kaplan Professor Department of Obstetrics and Gynecology, NYU Langone Medical Center, New York, NY, USA.