1. Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
2. Institute of Women’s Life Medical Science, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Obstetrics and Gynecology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
4. Department of Obstetrics and Gynecology, YongIn Severance Hospital, Yonsei University College of Medicine, YongIn City, Kyunggi-do, Korea
5. Department of Pathology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea