1. Department of Obstetrics and Gynecology; TweeSteden Hospital; Tilburg
2. Department of Obstetrics and Gynecology; Maxima Medical Center; Veldhoven
3. Department of Obstetrics and Gynecology; Radboud University Nijmegen Medical Center; Nijmegen
4. Department of Obstetrics and Gynecology; St. Antonius Hospital; Nieuwegein
5. Clinical Research Unit; Academic Medical Center; Amsterdam; the Netherlands
6. Department of Obstetrics and Gynecology; Academic Medical Center; Amsterdam