Patients with history of two or more recurrent pregnancy loss (RPL) and no history of living babies who had performed all investigations for recurrent miscarriage (RM) including : laboratory investigation ,trans vaginal ultrasound (TVS) ,autoimmune work up and hystroscopy and all results were free,will be scheduled for three dimensional trans-vaginal ultrasound (3D TVS) in the midluteal phase for measuring the impedance of uterine artery blood flow( by two dimensional Power Doppler TVS).Also by using 3D power Doppler the sub-endometrial blood flow will be assessed. In addition to the thickness of Junctional Zone (JZ) by using coronal view of 3 D TVS. To be compared with patients who had at least one full term living baby through normal vaginal delivery with no history of early pregnancy loss.