Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul 03080, Korea. bboddi0311@gmail.com. Department of Obstetrics and Gynecology, Cheil General Hospital & Women's Healthcare Center, Dankook University College of Medicine, Seoul 04619, Korea. asterik79@gmail.com. Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul 03080, Korea. marialeemd@gmail.com. Department of Obstetrics and Gynecology, Pusan National University School of Medicine, Busan 49241, Korea. kbs866@naver.com. Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam 13620, Korea. sdhwcj@naver.com. Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Seoul 03080, Korea. yssong@snu.ac.kr. Cancer Research Institute, Seoul National University College of Medicine, Seoul 110-799, Korea. yssong@snu.ac.kr.