1. Department of Obstetrics and Gynecology, Gyeongsang National University Changwon Hospital, Gyeongsang National University, Changwon, Korea
2. Department of Obstetrics and Gynecology, Gyeongsang National University Hospital, Gyeongsang National University, Jinju, Korea
3. Department of Occupational and Environmental Medicine, Gyeongsang National University Changwon Hospital, Gyeongsang National University, Changwon, Korea