1. Department of Midwifery and Reproductive Health, School of Nursing and Midwifery, Midwifery and Reproductive Health Research Center Shahid Beheshti University of Medical Sciences Tehran Iran
2. Department of Midwifery, School of Nursing and Midwifery Shiraz University of Medical Sciences Shiraz Iran
3. Department of Midwifery, Chalous Branch Islamic Azad University Chalous Iran
4. Department of Public Health, School of Public Health and Safety Shahid Beheshti University of Medical Sciences Tehran Iran
5. Department of Biostatistics Shahid Beheshti University of Medical Sciences Tehran Iran