[1] Linkoping Univ Hosp, Dept Mol & Clin Med, Div Obstet & Gynecol, Fac Hlth Sci, S-58185 Linkoping, Sweden
[2] Linkoping Univ Hosp, Fac Hlth Sci, Div Occupat & Environm Med, S-58185 Linkoping, Sweden
[3] Lund Univ, Dept Clin Sci Lund, S-22100 Lund, Sweden
[4] Lund Univ, Dept Clin Sci Malmo, S-22100 Lund, Sweden