1. Department of Obstetrics and Gynecology, Buddhachinnaraj Hospital and Naresuan University, Phitsanulok, Thailand.
2. Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital at Linkou and Chang Gung University College of Medicine, Kweishan, Taoyuan, Taiwan.
3. Department of Obstetrics and Gynecology, Bangkok Hospital, Bangkok, Thailand.