1. Department of Clinical, Surgical, Diagnostic and Paediatric Sciences, University of Pavia, 27100 Pavia, Italy
2. Department of Obstetrics and Gynecology, IRCCS Foundation Policlinico San Matteo, 27100 Pavia, Italy
3. Department of Obstetrics and Gynecology, L. Sacco Hospital, ASST-Fatebenefratelli-Sacco, University of Milan, 20157 Milan, Italy