1. Maastricht University Medical Centre; Department of Obstetrics and Gynaecology; P. Debyelaan 25 Maastricht Netherlands 6229 HX
2. Academic Medical Center; Department of Obstrics and Gynaecology; PO Box 22700 Amsterdam 1105DE Netherlands
3. Maastricht University Medical Center; Department of Obstetrics and Gynaecology, GROW; P. Debyelaan 25 Maastricht Netherlands 6202 AZ
4. Maastricht University; Department of Obstetrics and Gynaecology, Maastricht University Medical Centre; Department of Epidemiology; Maastricht Netherlands
5. Academic Medical Centre, University of Amsterdam; Obstetrics and Gynaecology; Meibergdreef 9 PO Box 22700 Amsterdam Netherlands 1105 AZ