1. Department of Obstetrics and Gynecology, University of the Philippines Manila, Philippine General Hospital at Manila, Manila, Philippines.
2. Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital at Linkou Medical Center, Kwei-Shan, Tao-Yuan, Taiwan.
3. Chang Gung University College of Medicine, Kwei-Shan, Tao-Yuan, Taiwan.