1. Department of Midwifery Science Amsterdam Public Health Amsterdam UMC Vrije Universiteit Amsterdam AVAG Amsterdam the Netherlands
2. Department of Obstetrics and Gynaecology Haga Ziekenhuis The Hague The Netherlands
3. Department of Obstetrics, Gynaecology and Reproductive Biology Harvard Medical School Boston Massachusetts USA
4. Department of Obstetrics and Gynaecology Erasmus MC Rotterdam the Netherlands
5. Department of Midwifery Science Amsterdam Reproduction and Development Amsterdam UMC Vrije Universiteit Amsterdam AVAG Amsterdam the Netherlands