1. Department of Obstetrics and Gynecology, Konkuk University School of Medicine, Seoul, Korea
2. Department of Obstetrics and Gynecology, Yonsei University College of Medicine, Seoul, Korea
3. Institute of Women’s Life Medical Science, Yonsei University College of Medicine, Seoul, Korea
4. Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
5. Department of Obstetrics and Gynecology, Institute of Women’s Life Medical Science, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Korea