1. Department of Gynecology, Obstetrics & Urology, University of Rome, Viale del Policlinico 155, 00161 Roma, Italy
2. Department of Obstetrics & Gynecology, Eastern Virginia Medical School, 700 W Olney Rd, Norfolk, VA 23507, USA
3. Leuven Institute for Fertility & Embryology, 3000 Leuven, Belgium