1 Department of Obstetrics and Gynecology, Kaohsiung Municipal Siaogung Hospital, Kaohsiung, Taiwan.
2 Department of Obstetrics and Gynecology, Chung Shan Medical University Hospital, 110, Jianguo N Rd, Section 1, Taichung, 402, Taiwan. gdchentw@hotmail.com.
3 Department of Women's Health, Dell Medical School, The University of Texas at Austin, Austin, TX, USA.