1 Department of Obstetrics and Gynecology, Korea University College of Medicine, Seoul, Korea.
2 Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, Korea.
3 Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea. drwon1@snu.ac.kr.
4 Division of Gastroenterology and Hepatology, Department of Internal Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea. drwon1@snu.ac.kr.