1 Department of Obstetrics and Gynaecology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium. Electronic address: isabelle.dehaene@ugent.be.
2 Department of Obstetrics and Gynaecology, Ghent University Hospital, Corneel Heymanslaan 10, 9000 Ghent, Belgium.