1. Department of Obstetrics and Gynecology; Healthcare System Gangnam Center; Seoul National University Hospital; Seoul Korea
2. The Institute of Reproductive Medicine and Population; Medical Research Centre; Seoul National University College of Medicine; Seoul Korea
3. Department of Obstetrics and Gynecology; Seoul National University College of Medicine; Seoul Korea
4. Department of Obstetrics and Gynecology; Konyang University College of Medicine; Daejeon Korea
5. Department of Obstetrics and Gynecology; Cheil General Hospital and Women's Healthcare Center; Kwandong University College of Medicine; Seoul Korea
6. Department of Obstetrics and Gynecology; Bundangcheil Women's Hospital; Bundang Korea
7. Department of Obstetrics and Gynecology; Seoul Rachel Fertility Center; Seoul Korea
8. Department of Obstetrics and Gynecology; Kyungpook National University College of Medicine; Daegu Korea