Esther Feijen-de Jong (Department of Midwifery Science Groningen, AVAG, Amsterdam Public Health research institute, VU University Medical Center, Amsterdam-Groningen, the Netherlands), Liesbeth Kool (Department of Midwifery Science Groningen, AVAG, Amsterdam Public Health research institute, VU University Medical Center, Amsterdam-Groningen, the Netherlands), Lilian Peters (Department of Midwifery Science Groningen, AVAG, Amsterdam Public Health research institute, VU University Medical Center, Amsterdam-Groningen, the Netherlands), Danielle Jansen (Department of Health Sciences, University Medical Center Groningen, University of Groningen, the Netherlands)