Maria S Pignotti1, Floriana Monciotti2, Paola Frati3, Vittorio Fineschi3. 1. Fetal and Neonatal Department, Anna Meyer Children Hospital, University of Firenze, Viale Pieraccini 24, 50139 Florence, Italy. Electronic address: maria.pignotti@meyer.it. 2. Department of Medical, Surgical and Neurological Sciences, University of Siena, Via delle Scotte, 53100 Siena, Italy. 3. Department SAIMLAL, Sapienza University of Rome, Viale Regina Elena 336, 00185 Rome, Italy.