[1] Univ Gothenburg, Sahlgrenska Acad, Dept Obstet & Gynecol, SE-41345 Gothenburg, Sweden
[2] Telemark Hosp, Div Obstet & Gynecol, N-3710 Skien, Norway
[3] Univ British Columbia, Dept Obstet & Gynecol, Vancouver, BC V5Z 1M9, Canada
[4] Univ Gothenburg, Sahlgrenska Acad, Dept Clin Pathol, SE-41345 Gothenburg, Sweden
[5] Telemark Hosp, Div Plast Surg, N-3710 Skien, Norway