[1] Vrije Univ Amsterdam, Med Ctr, Sect Mol Pathol, Dept Pathol, Amsterdam, Netherlands
[2] Vrije Univ Amsterdam, Med Ctr, Dept Obstet & Gynaecol, Amsterdam, Netherlands
[3] Vrije Univ Amsterdam, Med Ctr, Dept Clin Epidemiol & Biostat, Amsterdam, Netherlands
[4] Hosp Walcheren, Dept Obstet & Gynaecol, Vlissingen, Netherlands
[5] Erasmus MC, Dept Obstet & Gynaecol, Rotterdam, Netherlands