1. Department of Obstetrics, Birth Centre Wilhelmina Children Hospital, Division Women and Baby, University Medical Centre Utrecht, Utrecht, The Netherlands
2. Department of Obstetrics and Gynaecology, Diakonessenhuis, Utrecht, The Netherlands
3. Perined, Utrecht, The Netherlands
4. Department of Obstetrics and Gynaecology, Deventer Hospital, Deventer, The Netherlands
5. Department of Obstetrics and Gynaecology, Leiden University Medical Centre, Leiden, The Netherlands
6. Athena Institute, VU University, Amsterdam, The Netherlands