1. Department of Obstetrics and Gynecology, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
2. Department of Obstetrics and Gynecology, Kaohsiung Municipal Ta-Tung Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
3. Department of Obstetrics and Gynecology, Kaohsiung Municipal Siao-gang Hospital, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC