[1] Univ Groningen, Univ Med Ctr Groningen, Dept Obstet & Gynaecol, NL-9700 RB Groningen, Netherlands
[2] Isola Klin Zwolle, Dept Obstet & Gynaecol, Zwolle, Netherlands
[3] Med Ctr Leeuwarden, Dept Obstet & Gynaecol, Leeuwarden, Netherlands
[4] Leiden Univ, Med Ctr, Dept Obstet, Leiden, Netherlands
[5] Vrije Univ Amsterdam, Med Ctr, EMGO Inst Hlth & Care Res, Dept Med Humanities, Amsterdam, Netherlands