1. College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
2. Department of Obstetrics and Gynaecology, Sultan Qaboos University Hospital, Muscat 123, Oman
3. Department of Obstetrics and Gynaecology, Royal Hospital 111, Muscat 123, Oman
4. Department of Human and Clinical Anatomy, Sultan Qaboos University, Muscat 123, Oman