1. Department of Obstetrics & Gynecology, Chungnam National University School of Medicine, Chungnam National University Sejong Hospital, 20, Bodeum 7 ro, Sejong 30099, Republic of Korea
2. Department of Obstetrics & Gynecology, Chungnam National University School of Medicine, Chungnam National University Hospital, 33, Munhwa-ro, Jung-gu, Daejeon 35015, Republic of Korea