[1] Uppsala Univ, Dept Womens & Childrens Hlth, Uppsala, Sweden
[2] Sundsvall Hosp, Dept Obstet & Gynecol, Sundsvall, Sweden
[3] Karolinska Inst, Sect Obstet & Gynecol, Dept Clin Sci & Educ, Stockholm, Sweden
[4] Uppsala Univ, Uppsala Biomed Ctr, Dept Med Biochem & Microbiol, Uppsala, Sweden
[5] Sormland Uppsala Univ, Clin Res Ctr, Uppsala, Sweden
[6] St Georges Univ London, Dept Obstet & Gynecol, Div Clin Dev Sci, London, England