1 Fetal Medicine Unit, Di Venere and Sarcone Hospitals, ASL BA, Bari, Italy.
2 Department of Obstetrics and Gynecology, Maternal Fetal Medicine Unit, Palermo, Italy.
3 Maternal Infant Department SC, Obstetrics and Gynecology, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy.
4 Executive Board GIDIF-RBM, Milan, Italy.
5 Pathophysiology of Human Reproduction and Prenatal Diagnosis, Microcythemia Hospital Unit "A. CaO", Arnas Brotzu, Cagliari, Italy.
6 Operative Unit of Epidemiology and Statistics, IRCCS Institute of Neurological Sciences, Bologna, Italy.
7 Fetal Medicine Unit, Department for Women and Children Health, Careggi University and Hospital, Florence, Italy.
8 Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy.
9 Obstetrics and Gynecological Ultrasound and Prenatal Diagnosis Center, Citta' della Salute e della Scienza, Turin, Italy.
10 Unit of Fetal Medicine and Prenatal Diagnosis, Institute for Maternal and Child Health, IRCCS Burlo Garofolo, University of Trieste, Trieste, Italy.
11 Gynecology and Obstetrics, Rovereto and Trento Hospitals, ASST, Trento, Italy.
12 Department of Medicine and Surgery, Unit of Surgical Sciences, Obstetrics and Gynecology, University of Parma, Parma, Italy.