1
Centre for Reproductive Medicine and Department of Obstetrics and Gynaecology, Amsterdam University Medical Centre, Location AMC and VUMC, PO Box 22700, 1100 DE, Amsterdam, the Netherlands
2
Department of Reproductive Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands
3
Department of Obstetrics and Gynaecology, Maxima Medical Centre, Eindhoven, the Netherlands
4
Department of Obstetrics and Gynaecology, Leeuwarden Medical Centre, Leeuwarden, the Netherlands
5
Department of Obstetrics and Gynaecology, Isala Hospital Zwolle, Zwolle, the Netherlands
6
Department of Obstetrics and Gynaecology, University Medical Centre Leiden, Leiden, the Netherlands
7
Department of Obstetrics and Gynaecology, Jeroen Bosch Hospital, Den Bosch, the Netherlands
8
Department of Obstetrics and Gynaecology, Groene Hart Hospital, Gouda, the Netherlands
9
Department of Obstetrics and Gynaecology, Reinier de Graaf Gasthuis, Delft, the Netherlands
10
Department of Obstetrics and Gynaecology, Meander Medical Centre, Amersfoort, the Netherlands
11
Department of Obstetrics and Gynaecology, Ikazia Hospital, Rotterdam, the Netherlands
12
Department of Obstetrics and Gynaecology, OLVG Oost, Amsterdam, the Netherlands
13
Department of Obstetrics and Gynaecology, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
14
Department of Obstetrics and Gynaecology, Nijmegen, the Netherlands
15
Department of Obstetrics and Gynaecology, Elisabeth Hospital Tweesteden, Tilburg, the NetherNetherlandslands
16
Department of Obstetrics and Gynaecology, Birmingham Women’s and Children’s Hospital, Birmingham, UK
17
Department of Obstetrics and Gynaecology, University of Illinois, CA, USA
18
Department of Obstetrics and Gynaecology, Monash University, Monash Medical Centre, Clayton, Victoria, Australia
✉Correspondence address. Tel: 31-20-566 3857; Fax: 31-20-696 3489; E-mail: j.f.rikken@amsterdamumc.nl, m.goddijn@amsterdamumc.nl