1. Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
2. ESHRE Central Office, Belgium
3. Institute of Reproductive Medicine and Gynecological Endocrinology (RME), Basel, Switzerland
4. Center for Reproductive Medicine, Gynaekologicum Hamburg, Hamburg, Germany
5. Cliniques Universitaires Saint Luc, Université Catholique de Louvain, Brussels, Belgium
6. Rotunda Hospital and Royal College of Surgeons in Ireland, Dublin, Ireland
7. Human Reproduction Center Budva, Budva, Montenegro
8. Registro Nazionale della Procreazione Medicalmente Assistita, Istituto Superiore di Sanità, Roma, Italy
9. Department of Obstetrics and Gynaecology, Elisabeth Twee Steden Hospital, Tilburg, The Netherlands
10. Clinical Center Serbia, ``GAK'' Institute for Obstetrics and Gynecology, Belgrade, Serbia