[1] Saiseikai Mastusaka General Hospital,Department of Obstetrics and Gynecology
[2] Mie University School of Medicine,Department of Obstetrics and Gynecology
[3] Kyoto University,Department of Human Health Sciences, Graduate School of Medicine
[4] Tokyo Metropolitan Tama Medical Center,Department of Obstetrics and Gynecology
[5] Ministry of Health,Regional Medical Care Planning Division, Health Policy Bureau
[6] Saitama Medical Center,Department of Obstetrics and Gynecology
[7] Saitama Medical University,Department of Acute Medicine, Division of Emergency and Critical Care Medicine
[8] Nihon University School of Medicine,undefined
[9] Japan Resuscitation Council,undefined