1. Department of Maternal-Fetal Medicine; Osaka Medical Center and Research Institute for Maternal and Child Health
2. Department of Obstetrics and Gynecology; Osaka University
3. Department of Obstetrics and Gynecology; Aizenbashi Hospital
4. Department of Obstetrics and Gynecology; Rinku General Medical Center, Osaka
5. Department of Obstetrics and Gynecology; Hyogo Prefectural Nishinomiya Hospital; Hyogo Japan