1. Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung 407219, Taiwan
2. Department of Obstetrics and Gynecology, Chung Shan Medical University Hospital, Taichung 402306, Taiwan
3. Department of Obstetrics and Gynecology, School of Medicine, College of Medicine, Chung Shan Medical University, Taichung 402306, Taiwan