1. Department of Obstetrics and Gynaecology, Faculty of Medicine, The University of British Columbia, Vancouver, Canada.
2. Department of Obstetrics and Gynaecology, Faculty of Medicine, Sohag University, Sohag, Egypt.
3. Department of Obstetrics and Gynaecology, Faculty of Medicine, Assiut University, Assiut, Egypt.
4. Department of Obstetrics and Gynaecology, School of Medicine, Case Western Reserve University, Cleveland, Ohio.
5. Department of Obstetrics and Gynaecology, School of Medicine, Duke University, Durham, North Carolina.