1. Department of Obstetrics and Gynecology; Aiwa Hospital; Kawagoe Saitama
2. Perinatology Committee; Japan Society of Obstetrics and Gynecology; Tokyo
3. Department of Obstetrics and Gynecology; Hamamatsu Medical Center; Hamamatsu
4. Japan Society of Obstetrical; Gynecological and Neonatal Hematology; Fukuoka Japan
5. Division of Obstetrics, Center of Maternal-Fetal, Neonatal and Reproductive Medicine; National Center for Child Health and Development
6. Department of Perinatology and Gynecology; Kagawa University Graduate School of Medicine; Miki
7. Department of Obstetrics and Gynecology; Juntendo University Faculty of Medicine
8. Department of Obstetrics and Gynecology; Nagasaki University Faculty of Medicine; Nagasaki