1. Department of Obstetrics and Gynecology, Mie University School of medicine, Tsu, Japan.
2. Department of Obstetrics and Gynecology, Tokyo Women's Medical University, Tokyo, Japan.
3. Department of Obstetrics and Gynecology, St. Marianna University School of Medicine, Kawasaki, Japan.
4. Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan.
5. Department of Obstetrics and Gynecology, Kyushu University School of Medicine, Fukuoka, Japan.
6. Division of Clinical Research, Global Clinical Research Coordinating Center, Kitasato University, Tokyo, Japan.
7. Department of Obstetrics and Gynecology, Osaka City General Hospital, Osaka, Japan.
8. Department of Obstetrics and Gynecology, Saitama Medical University International Medical Center, Hidaka, Japan.
9. Department of Obstetrics and Gynecology, Kosei General Hospital, Kutchan, Japan.
10. Department of Obstetrics and Gynecology, Tokyo Medical University School of Medicine, Tokyo, Japan.
11. Department of Obstetrics and Gynecology, Osaka City University School of Medicine, Osaka, Japan.
12. Department of Obstetrics and Gynecology, The Jikei University School of Medicine, Tokyo, Japan.
13. Department of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, Japan.
14. Department of Obstetrics and Gynecology, Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan.
15. Department of Obstetrics and Gynecology, Iwate Medical University School of Medicine, Morioka, Japan.