[1] TNO Prevent & Hlth, NL-2301 CE Leiden, Netherlands
[2] Univ Hosp St Radboud, Dept Obstet & Gynaecol, Nijmegen, Netherlands
[3] Leiden Univ, Med Ctr, Dept Obstet & Gynaecol, Leiden, Netherlands
[4] Diaconessen Hosp, Dept Obstet & Gynaecol, Voorburg, Netherlands
[5] Univ Med Ctr, Dept Obstet & Gynaecol, Utrecht, Netherlands
[6] Isala Clin, Dept Obstet & Gynaecol, Zwolle, Netherlands
[7] Erasmus Med Ctr, Dept Obstet & Gynaecol, Rotterdam, Netherlands