1. Department of Obstetrics and Gynecology, Daejeon St. Mary’s Hospital, The Catholic University of Korea, Daejeon, Korea.
2. Department of Obstetrics and Gynecology, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea.
3. Department of Obstetrics and Gynecology, Institute of Women’s Medical Life Science, Yonsei Cancer Center, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, Korea.
5. Department of Obstetrics and Gynecology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
6. Department of Obstetrics and Gynecology, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
7. Department of Obstetrics and Gynecology, Keimyung University Dongsan Medical Center, Daegu, Korea.
8. Department of Obstetrics and Gynecology, CHA Ilsan Medical Center, CHA University, Goyang, Korea.
9. Department of Obstetrics and Gynecology, Hallym University Kangnam Sacred Heart Hospital, Seoul, Korea.
10. Department of Obstetrics and Gynecology, Wonju Severance Christian Hospital, Yonsei University College of Medicine, Wonju, Korea.
11. Department of Obstetrics and Gynecology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea.
12. Department of Obstetrics and Gynecology, Hanyang University Medical Center, Seoul, Korea.