1. Department of Obstetrics and Gynecology , Hadassah-Hebrew University Medical Center , Jerusalem , Israel
2. Department of Obstetrics and Gynecology , Chaim Sheba , Ramat Gan , Afilliated to Tel-Aviv university , Tel-Aviv , Israel .
3. Shaare Zedek Medical Center , Jerusalem , Israel
4. Department of Obstetrics and Gynecology , Meuhedet HMO , Jerusalem , Israel