1. Department of Obstetrics and Gynecology CHA Bundang Medical Center CHA University School of Medicine Seongnam Republic of Korea
2. Department of Obstetrics and Gynecology Seoul National University College of Medicine Seoul Republic of Korea
3. Department of Biostatistics Seoul Metropolitan Government Seoul National University Boramae Medical Center Seoul Republic of Korea
4. Department of Preventive Medicine Korea University Seoul Republic of Korea
5. Institute of Reproductive Medicine and Population Seoul National University Medical Research Center Seoul Republic of Korea