1. Department of Obstetrics and Gynecology, Zaans Medical Center, Zaandam, The Netherlands
2. Department of Obstetrics and Gynecology, Amsterdam UMC, location VU University Medical Center, Amsterdam, The Netherlands
3. Clinical Epidemiology, Biostatistics and Bioinformatics, Master Evidence Based Practice in Health Care, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands