1. Department of Obstetrics and Gynaecology; University of Brescia; Brescia Italy
2. Department of Obstetrics and Gynaecology; University of Verona; Verona Italy
3. Children's Hospital V. Buzzi; Milan Italy
4. Department for Woman and Child Health; AOU Careggi, Florence Italy
5. Unit of Prenatal Diagnosis, Institute for Maternal and Child Health; IRCCS Burlo Garofolo; Trieste Italy