1. Department of Obstetrics and Gynaecology, “St. Sofia” Hospital, Sofia, Bulgaria
2. Department of Medical Biology, Medical Faculty, Medical University, Sofia, Bulgaria
3. Department of Chemistry and Biochemistry, Medical University, Sofia, Bulgaria
4. Clinic of Endocrinology, “Alexandrovska” Hospital, Medical University, Sofia, Bulgaria
5. Department of Medical Physics and Biophysics, Medical University, Sofia, Bulgaria