1. Obstetrics and Gynaecology; Radboud University Medical Centre; Nijmegen the Netherlands
2. Obstetrics and Gynaecology; Maastricht University Medical Centre; Maastricht the Netherlands
3. Obstetrics and Gynaecology; Atrium Medical Centre Parkstad; Heerlen the Netherlands
4. Epidemiology; Maastricht University Medical Centre; Maastricht the Netherlands
5. Obstetrics and Gynaecology; Academic Medical Centre; Amsterdam the Netherlands
6. Radiology; Maastricht University Medical Centre; Maastricht the Netherlands
7. Radiology; Atrium Medical Centre Parkstad; Heerlen the Netherlands
8. Obstetrics and Gynaecology; Orbis Medical Centre; Sittard the Netherlands
9. Obstetrics and Gynaecology; Laurentius Medical Centre; Roermond the Netherlands