1. Department of Preventive Medicine, The Catholic University of Korea College of Medicine, Seoul, Korea.
2. Department of Obstetrics and Gynecology, Cheil General Hospital and Women's Healthcare Center, Kwandong University College of Medicine, Seoul, Korea.
3. Department of Obstetrics and Gynecology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
4. Department of Pathology, Cheil General Hospital and Women's Healthcare Center, Kwandong University College of Medicine, Seoul, Korea.
5. Division of AIDS, Center for Immunology and Pathology, National Institute of Health, Korea Centers for Disease Control and Prevention, Cheongwon, Korea.
6. Department of Obstetrics and Gynecology, Chonnam National University Medical School, Gwangju, Korea.
7. Department of Obstetrics and Gynecology, Keimyung University Dongsan Medical Center, Daegu, Korea.
8. Department of Obstetrics and Gynecology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.