1. Department of Obstetrics and Gynecology; Hallym University Sacred Heart Hospital; Hallym University College of Medicine; Anyang Korea
2. East-West Medical Research Institute; Kyung Hee University; Seoul Korea
3. Department of Preventive Medicine; School of Medicine; Kyung Hee University; Seoul Korea
4. Eulji University; School of Medicine; Daejeon Korea
5. Department of Obstetrics and Gynecology; St. Vincent's Hospital; College of Medicine; The Catholic University of Korea; Suwon Korea