1 Department of Obstetrics and Gynecology, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.
2 Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul, South Korea.
3 Department of Obstetrics and Gynecology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, South Korea.
4 Department of Obstetrics and Gynecology, University of Ulsan College of Medicine, Ulsan University Hospital, Ulsan, South Korea.
5 Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 06273, South Korea.
6 Institute of Women's Life Medical Science, Yonsei University College of Medicine, Seoul, South Korea. sihyuncho@yuhs.ac.
7 Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul, 06273, South Korea. sihyuncho@yuhs.ac.