[1] Univ Turku, Inst Biomed, Turku, Finland
[2] Turku Univ Hosp, Dept Obstet & Gynecol, Turku, Finland
[3] Tampere Univ Hosp, Dept Obstet & Gynecol, Tampere, Finland
[4] Univ Helsinki, Dept Pathol, Helsinki, Finland
[5] Helsinki Univ Hosp, HUSLAB, Helsinki, Finland
[6] Gothenburg Univ, Sahlgrenska Acad, Inst Med, Gothenburg, Sweden