Affiliation: | (1) Department of Obstetrics and Gynecology, Division of Maternal Fetal Medicine, The University of Oklahoma Health Sciences Center, PO Box 26901, WP 2470, Oklahoma City, OK 73126, USA;(2) The College of Public Health, Department of Biostatistics and Epidemiology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA;(3) The Perinatal Center of Oklahoma, Oklahoma City, OK, USA |