[1] Univ Groningen, Groningen, Netherlands
[2] Univ Groningen, Univ Med Ctr Groningen, Dept Hlth Sci, Groningen, Netherlands
[3] Univ Groningen, Univ Med Ctr Groningen, Dept Primary & Long Term Care, Hanzepl 1, NL-9713 GZ Groningen, Netherlands
[4] Vrije Univ Amsterdam, Amsterdam Univ Med Ctr, Amsterdam Publ Hlth Res Inst, Dept Midwifery Sci, Amsterdam, Netherlands
[5] Midwifery Acad Amsterdam Groningen, Groningen, Netherlands