1. Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan
2. Department of Obstetrics and Gynecology, Chi Mei Foundation Hospital, Tainan 710, Taiwan
3. Department of Obstetrics and Gynecology, Kaohsiung Municipal Hsiao-Kang Hospital, Kaohsiung Medical University, 100 Shih-Chuan Road, San-Min District, Kaohsiung 80708, Taiwan