1. Department of Medical and Surgical Sciences, University of Padua, Padua, Italy.
2. Department of Endocrinology and Metabolic Diseases, University of Pisa, Pisa, Italy.
3. Department of Gynecology, Perinatology and Human Reproduction, University of Florence, Florence, Italy.
4. A. Menarini Diagnostics, Florence, Italy.
5. CNR, Institute of Clinical Physiology, Pisa, Italy.