Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Center for Assisted Reproductive Technology, Division of Obstetrics and Gynecology, Careggi University Hospital, Florence, Italy. Center for Assisted Reproductive Technology, Division of Obstetrics and Gynecology, Careggi University Hospital, Florence, Italy. Center for Assisted Reproductive Technology, Division of Obstetrics and Gynecology, Careggi University Hospital, Florence, Italy; Department of Clinical and Experimental Biomedical Sciences, University of Florence, Florence, Italy. Department of Experimental and Clinical Medicine, University of Florence, Florence, Italy; Center for Assisted Reproductive Technology, Division of Obstetrics and Gynecology, Careggi University Hospital, Florence, Italy. Electronic address: cinzia.fatini@unifi.it.