1. D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductive Medicine, Department of Obstetrics, Division of Maternal-Fetal Medicine, St. Petersburg, Russia; 3 Mendeleevskaya Line, St. Petersburg Russia
2. St. Petersburg State University, Faculty of Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, St. Petersburg, Russia
3. Department of Immunology and Microbiology, University of Gothenburg, Gothenburg, Sweden