1. Department of Obstetrics and Gynecology, Ewha Womans University Mokdong Hospital, Seoul, Korea.
2. Department of Obstetrics and Gynecology, WCU Biomodulation in Major, Cancer Research Institute, Seoul National University Hospital, Seoul, Korea.
3. Department of Obstetrics and Gynecology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.
4. Department of Obstetrics and Gynecology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
5. Department of Obstetrics and Gynecology, St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea.
6. GlaxoSmithKline Biologicals, Wavre, Belgium.
7. Department of Obstetrics and Gynecology, Seoul St. Mary's Hospital, The Catholic University of Korea School of Medicine, Seoul, Korea.