1 Department of Obstetrics and Gynecology, Bangkok Hospital, Bangkok, Thailand; Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital at Linkou, Kweishan, Taoyuan, Taiwan.
2 Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital at Linkou, Kweishan, Taoyuan, Taiwan; Department of Obstetrics and Gynecology, Buddhachinnaraj Hospital and Naresuan University, Phitsanulok, Thailand.
3 Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital at Linkou, Kweishan, Taoyuan, Taiwan; Chang Gung University College of Medicine, Kweishan, Taoyuan, Taiwan. Electronic address: kghuang@ms57.hinet.net.