1. Department of Obstetrics and Gynecology, Osaka University Graduate School of Medicine, Suita, Osaka 567‑0871, Japan
2. Department of Obstetrics and Gynecology, Niigata University Graduate School of Medicine, Chuo-ku, Niigata 951‑8520, Japan
3. Department of Obstetrics and Gynecology, Kanazawa Medical University, Uchinada, Ishikawa 920‑0293, Japan
4. Department of Obstetrics and Gynecology, University of Occupational and Environmental Health, Kitakyushu, Fukuoka 807‑8556, Japan
5. Department of Obstetrics and Gynecology, Kawasaki Medical University, Kurashiki, Okayama 701‑0192, Japan
6. Hiramatsu Obstetrics and Gynecology Clinic, Kishiwada-shi, Osaka 583‑0024, Japan
7. Saito Women Clinic, Yodogawa-ku, Osaka 532‑0003, Japan
8. Ladies Clinic Yagi, Senboku-gunn, Osaka 595‑0805, Japan
9. Maki Ladies Clinic, Ibaraki-shi, Osaka 567‑0031, Japan