1 Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.138, Sheng Li Rd., Tainan 704, R.O.C, Taiwan.
2 Department of Obstetrics and Gynecology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, No.138, Sheng Li Rd., Tainan 704, R.O.C, Taiwan. Electronic address: tsaipy@mail.ncku.edu.tw.