[1] Department of Obstetrics and Gynecology, Hopital Universitaire Brugmann Université Libre de Bruxelles, Brussels
[2] Department of Obstetrics and Gynecology, Centre Hospitalier Régional de la Citadelle, Université de Liège, Liège
[3] Department of Obstetrics and Gynecology, Hopital civil de Charleroi, Charleroi
[4] Department of Obstetrics and Gynecology, Hopital de la Madeleine, Ath
[5] Department of Obstetrics and Gynecology, Akademisch Ziekenhuis, Rijksuniversiteit Gent, Gent