1. Department of Obstetrics & Gynecology, Uijeongbu St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Uijeongbu-si 11765, Gyeonggi-do, Republic of Korea
2. Department of Obstetrics and Gynecology, Inha University Hospital, College of Medicine, Inha University, 27, Inhang-ro, Sinheung-dong, Jung-gu, Incheon 22332, Republic of Korea
3. Medical Science Research Center, College of Medicine, Korea University, 73, Goryeodae-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
4. Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, 82, Gumi-ro 173 beon-gil, Bundang-gu, Seongnam-si 13620, Gyeonggi-do, Republic of Korea