1. Department of Obstetrics and Gynaecology, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Obstetrics and Gynecology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
3. Department of Pathology, Cheil General Hospital & Women’s Healthcare Center, Dankook University College of Medicine, Seoul, Korea.
4. Department of Obstetrics and Gynecology, Ewha Womans University Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea.
5. Department of Obstetrics and Gynecology, Gachon University Gil Medical Center, Gachon University College of Medicine, Incheon, Korea.
6. Department of Obstetrics and Gynecology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
7. Department of Obstetrics and Gynecology, Research Institute of Medical Science, Konkuk University School of Medicine, Seoul, Korea.
8. Department of Obstetrics and Gynecology, Pusan National University Yangsan Hospital, Pusan National University School of Medicine, Yangsan, Korea.
9. Department of Obstetrics and Gynecology, Dongguk University Ilsan Hospital, Dongguk University College of Medicine, Goyang, Korea.
10. Departments of Obstetrics and Gynecology, Ajou University School of Medicine, Suwon, Korea.
11. Department of Obstetrics and Gynecology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Korea.