1. Department of Obstetrics and Gynecology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University Collage of Medicine, Kaohsiung 833401, Taiwan
2. Department of Obstetrics and Gynecology, Jiannren Hospital, Kaohsiung 811020, Taiwan
3. Department of Obstetrics and Gynecology, Fangliao General Hospital, Pingtung 940004, Taiwan