1 Obstetrics and Gynaecology, Radboud University Medical Centre, Geert Grooteplein Zuid 10 (route 791), Postbox 9101, 6500 HB, Nijmegen, The Netherlands. kim.vandelft@radboudumc.nl.
2 ST7 Obstetrics and Gynaecology, Basingstoke and North Hampshire Hospital, Basingstoke, UK.