1. Department of Obstetrics and Gynecology, Groene Hart Hospital, Gouda, The Netherlands
2. Department of Obstetrics, Academic Medical Center, Amsterdam, The Netherlands
3. Department of Obstetrics, VU Medical Center, Amsterdam, The Netherlands
4. Department of Obstetrics and Gynecology, Haga Hospital, the Hague, The Netherlands
5. Department of Obstetrics, Maastricht University Medical Center, Maastricht, The Netherlands
6. Department of Obstetrics and Gynecology, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands
7. Department of Obstetrics and Gynecology, Ikazia Hospital, Rotterdam, The Netherlands
8. Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands