1. Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Obstetrics and Gynecology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul, Korea.
3. The Institute of Reproductive Medicine and Population, Medical Research Centre, Seoul National University College of Medicine, Seoul, Korea.
4. Department of Obstetrics and Gynecology, Healthcare System Gangnam Center, Seoul National University Hospital, Seoul, Korea.
5. Department of Obstetrics and Gynecology, Konyang University College of Medicine, Daejeon, Korea.
6. Department of Obstetrics and Gynecology, Cheil General Hospital and Women's Healthcare Center, Dankook University, College of Medicine, Seoul, Korea.
7. Department of Obstetrics and Gynecology, Bundang Cheil Women's Hospital, Sungnam, Korea.
8. Department of Obstetrics and Gynecology, Seoul Rachel Fertility Center, Seoul, Korea.
9. Department of Obstetrics and Gynecology, Graduate School of Medicine, Dongguk University, Seoul, Korea.