1. Prenatal Diagnostic Service, Division of Obstetrics & Gynecology, Guastalla Civil Hospital, AUSL Reggio Emilia, Italy
2. Prenatal Diagnostic Service, Florence, Italy
3. Prenatal Diagnostic Service, Siena, Italy
4. Preconceptional and Prenatal Physiopathology Service, Galliera Hospital, Genoa, Italy
5. Istituti Clinici di Perfezionamento, Ospedale del Bambino “V. Buzzi”