1. Department of Obstetrics and Gynecology, Leiden University Medical Centre, Leiden, The Netherlands
2. Department of Obstetrics and Gynecology, Academic Medical Centre, Amsterdam, The Netherlands
3. Department of Obstetrics and Gynecology, University Medical Centre, Utrecht, The Netherlands
4. Department of Obstetrics and Gynecology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands
5. Department of Obstetrics and Gynecology, Spaarne Hospital, Hoofddorp, The Netherlands
6. The Robinson Research Institute, School of Medicine, University of Adelaide, South Australia, Australia