1. Department of Gynecological Endocrinology, Poznan University of Medical Sciences, Poznan, Poland;
2. Department of Reproductive Medicine and Child Development, Division of Gynecology and Obstetrics, University of Pisa, Pisa, Italy;
3. Department of Obstetrics and Gynecology, Gynecological Endocrinology Center, University of Modena and Reggio Emilia, Modena, Italy