1. Department of Obstetrics and Gynaecology Amsterdam UMC University of Amsterdam Amsterdam the Netherlands
2. Department of Obstetrics and Gynaecology Medical Spectrum Twente Enschede the Netherlands
3. School for Public Health and Primary Care University of Maastricht Maastricht the Netherlands
4. Department of Obstetrics and Gynaecology Leiden University Medical Centre Leiden the Netherlands
5. Department of Obstetrics and Gynaecology Isala Clinic Zwolle the Netherlands