1. Department of Midwifery Science; AVAG and the EMGO Institute for Health and Care Research; VU University Medical Centre; Amsterdam The Netherlands
2. Department of Obstetrics and Gynecology; Staff-Specialist Maternal and Fetal medicine; University Medical Center Groningen; Groningen The Netherlands
3. Netherlands institute for health services research (NIVEL); Utrecht The Netherlands
4. Department of Midwifery Science; EMGO+VUMc; Amsterdam The Netherlands