Unexplained Recurrent miscarriage remains a frustrating problem for the clinician and a distressing condition for the affected couple. Our study was performed at performed Kasr El Aini maternity hospital outpatient clinic in which were classified into two groups. (Group A): 50 participants presented with a history of idiopathic recurrent pregnancy loss (the RPL group) and (Group B) : 50 participants who had no history of abortion and at least 1 child born at term (the control group). All of them were subjected to two dimensional ultrasound, power Doppler for measurement of uterine artery pulsatility index and 3D power Doppler ultrasound on endometrium and subendometrium to calculate vascularity index(VI), flow index(FI) and vascular flow index(VFI) using VOCAL (virtual organ computer aided analysis) technique.