1. Department of Obstetrics and Gynaecology, Riga Stradins University, LV-1007 Riga, Latvia
2. Riga Maternity Hospital, LV-1013 Riga, Latvia
3. Scientific Laboratory of Molecular Genetics, Riga Stradins University, LV-1007 Riga, Latvia
4. Department of Statistics, Riga Stradins University, LV-1007 Riga, Latvia
5. Institute of Life Sciences and Technologies, Daugavpils University, LV-5401 Daugavpils, Latvia