1. Clinic of Obstetrics and Gynaecology, Department of Clinical Sciences, Università Politecnica delle Marche, Salesi Hospital, Azienda Ospedaliero Universitaria, Ancona, Italy
2. Department of Experimental and Clinical Medicine, Università Politecnica delle Marche, Ancona, Italy
3. Department of Biomedical and Surgical Science, Clinic of Obstetrics and Gynecology, University of Perugia, Perugia, Italy
4. Centre of Perinatal and Reproductive Medicine, Department of Obstetrics and Gynecology, University of Perugia, Perugia, Italy
5. Centre of Epidemiology and Biostatistics, Università Politecnica delle Marche, Ancona, Italy