[1] Vrije Univ Amsterdam, Amsterdam Univ, Midwifery Acad Amsterdam Groningen, Inholland,Med Ctr, Amsterdam, Netherlands
[2] Midwifery Acad Amsterdam Groningen, InHolland, Amsterdam, Netherlands
[3] Amsterdam Publ Hlth, Qual Care, Amsterdam, Netherlands
[4] Univ Groningen, Univ Med Ctr Groningen, Dept Gen Practice & Elderly Care Med, Groningen, Netherlands
[5] Univ Nottingham, Sch Hlth Sci, Dept Midwifery, Nottingham, England
[6] Maxima Med Ctr, Dept Obstet & Gynaecol, Veldhoven, Netherlands
[7] Radboud Univ Nijmegen, Amalia Childrens Hosp, Dept Obstet & Gynaecol, Med Ctr, Nijmegen, Netherlands
[8] Amsterdam Univ Med Ctr, Amsterdam Univ, Dept Obstet & Gynaecol, Med Ctr, Amsterdam, Netherlands
[9] Amsterdam Reprod & Dev Res Inst, Amsterdam, Netherlands
[10] Isala Women & Childrens Hosp, Dept Obstet & Gynecol, Zwolle, Netherlands
[11] Boelelaan 1117, NL-1081 HV Amsterdam, Netherlands