1. Gynecology and Assisted Reproduction Hospital “Malinov DM”, 1680 Sofia, Bulgaria
2. Department of Biology, Medical Genetics and Microbiology, Faculty of Medicine, Sofia University “St. Kliment Ohridski”, 1407 Sofia, Bulgaria
3. Medical Center “Femina”, 1202 Sofia, Bulgaria
4. University Ob/Gyn Hospital “Maichin Dom” and Department of Obstetrics and Gynecology, Medical University of Sofia, 1431 Sofia, Bulgaria
5. Department of Medical Genetics, Medical University of Sofia, 1431 Sofia, Bulgaria