1Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Korea.
2Department of Obstetrics and Gynecology, Kyungpook National University School of Medicine, Daegu, Korea.
3Department of Obstetrics and Gynecology, Yonsei University College of Medicine, Seoul, Korea.
4Department of Obstetrics and Gynecology, Hanyang University College of Medicine, Seoul, Korea.
5Department of Obstetrics and Gynecology, Ajou University School of Medicine, Suwon, Korea.
6Department of Obstetrics and Gynecology, Cheil General Hospital, Kwandong University College of Medicine, Seoul, Korea.
7Gwangju Mirae & Heemang Obstetrics and Gynecology Clinic, Gwangju, Korea.
8Hamchoon Women's Clinic, Seoul, Korea.
9Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
10Mirae & Heemang Obstetrics and Gynecology Clinic, Seoul, Korea.
11Maria Fertility Hospital, Seoul, Korea.
12Department of Obstetrics and Gynecology, Keimyung University School of Medicine, Daegu, Korea.
13Department of Obstetrics and Gynecology, Pusan National University School of Medicine, Yangsan, Korea.
14Bucheon Seoul Women's Hospital, Bucheon, Korea.
15Department of Obstetrics and Gynecology, Chung-Ang University College of Medicine, Seoul, Korea.
16Mudeung Mountain Eco Hospital, Damyang, Korea.
17Good Moonhwa Hospital, Busan, Korea.
18Mizmedi Hospital, Seoul, Korea.
19Department of Obstetrics and Gynecology, CHA University College of Medicine, Pocheon, Korea.