1. Health Promotion Center, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
2. Department of Obstetrics and Gynecology, Ajou University School of Medicine, Suwon, Korea.
3. Department of Molecular Science and Technology, Ajou University, Suwon, Korea.
4. Department of Obstetrics and Gynecology, Bundang Jesaeng Hospital, Seongnam, Korea.