1. Department of Obstetrics and Gynecology; Kangdong Sacred Heart Hospital; Hallym University; Seoul Korea
2. Department of Pathology; Kangdong Sacred Heart Hospital; Hallym University; Seoul Korea
3. Integrated Research Center for Genome Polymorphism; Department of Microbiology; College of Medicine; The Catholic University of Korea; Seoul Korea
4. Department of Obstetrics and Gynecology; Saint Vincent's Hospital; The Catholic University of Korea; Seoul Korea
5. Department of Obstetrics and Gynecology; Korea University; Ansan Hospital; Ansan Korea
6. Department of Obstetrics and Gynecology; Soonchunhyang University College of Medicine; Cheonan Korea
7. Department of Obstetrics and Gynecology; Hanyang University College of Medicine; Seoul Korea
8. Department of Obstetrics and Gynecology; Dongsan Medical Center, Keimyung University; Daegu Korea
9. Department of Public Health Administration; Namseoul University; Chunan Korea