1 Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Obstetrics and Gynecology, and Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.
2 Department of Obstetrics and Gynecology, Taipei Veterans General Hospital, Taipei, Taiwan; Department of Obstetrics and Gynecology, and Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan; Department of Medical Research, China Medical University Hospital, Taichung, Taiwan. Electronic address: phwang@vghtpe.gov.tw.