1. Department of Obstetrics and Gynecology, Graduate School of Medicine, Mie University, Tsu, Japan.
2. Department of Obstetrics and Gynecology, St. Marianna University School of Medicine, Kawasaki, Japan.
3. Department of Obstetrics and Gynecology, Graduate School of Medicine, Gifu University, Gifu, Japan.
4. Department of Obstetrics and Gynecology, Tokyo Rosai Hospital, Ohta-ku, Japan.
5. Department of Gynecology and Obstetrics, Graduate School of Medical Science, Kyoto University, Sakyo-ku, Japan.
6. Department of Obstetrics and Gynecology, Jichi Medical University, Shimotsuke, Japan.
7. Department of Obstetrics and Gynecology, Saitama Medical Center, Kawagoe, Japan.
8. Department of Obstetrics and Gynecology, Nara Medical University, Kashihara, Japan.