1. Third Department of Obstetrics and Gynecology, Medical School, University General Hospital “ATTIKON”, National and Kapodistrian University of Athens, 12462 Athens, Greece
2. First Department of Obstetrics and Gynecology, Medical School, Alexandra Hospital, National and Kapodistrian University of Athens, 11528 Athens, Greece
3. Department of Obstetrics and Gynecology, Royal Cornwall Hospital, Treliske, Truro TR1 3LQ, UK
4. Department of Obstetrics and Gynecology, Medical School of the University of Ioannina, 45110 Ioannina, Greece