1. Unit of Maternal-Fetal-Medicine, Department of Obstetrics and Gynecology, Medical School, Democritus University of Thrake, GR-68100 Alexandroupolis, Greece
2. First Department of Obstetrics and Gynecology, Medical School, National and Kapodistrian University of Athens, GR-11528 Athens, Greece
3. First Department of Obstetrics and Gynecology, Medical School, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Greece
4. Second Department of Obstetrics and Gynecology, Medical School, Aristotle University of Thessaloniki, GR-54640 Thessaloniki, Greece
5. Second Department of Obstetrics and Gynecology, Medical School, National and Kapodistrian University of Athens, GR-11528 Athens, Greece
6. Third Department of Obstetrics and Gynecology, Medical School, Aristotle University of Thessaloniki, GR-54640 Thessaloniki, Greece