Affiliation: | a Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Jefferson Medical College, Thomas Jefferson University, Philadelphia, PA b Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Alabama, Birmingham, AL c Department of Biostatistics, University of Alabama, Birmingham, AL d Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, TX e Department of Obstetrics and Gynecology, The Ohio State University Medical Center, Columbus, OH f Department of Obstetrics and Gynecology, University of Texas Southwestern Medical Center, Dallas, TX g Department of Obstetrics and Gynecology, College of Physicians and Surgeons, Columbia University, New York, NY h Department of Obstetrics and Gynecology, University of California, Irvine, Irvine, CA i Department of Obstetrics and Gynecology, Saint Peter's University Hospital, New Brunswick, NJ |