1. Department of Family Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
2. Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
3. Department of Pathology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.