1. Department of Obstetrics and Gynecology, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
2. Department of Obstetrics and Gynecology, Keio University School of Medicine, Tokyo, Japan.
3. Department of Information Science, Iwate Medical University, Iwate, Japan.
4. Department of Gynecology, Tohoku University Hospital, Miyagi, Japan.
5. Department of Healthcare Administration, Nagoya University Graduate School of Medicine, Nagoya, Japan.
6. Department of Obstetrics and Gynecology, Hirosaki University Graduate School of Medicine, Aomori, Japan.
7. Department of Obstetrics and Gynecology, University of Occupational and Environmental Health, Fukuoka, Japan.
8. Department of Obstetrics and Gynecology, Nihon University School of Medicine, Tokyo, Japan.
9. Department of Obstetrics and Gynecology, Yamagata University, Yamagata, Japan.