Recurrent abortion is a distressing problem for both clinicians and fertile couples a well. And when being unexplained is more frustrating. Endometrial receptivity was thought to be responsible for about two-thirds of these cases. Uterine perfusion is one of factors responsible for it. And as uterine artery is he main blood supply to the uterus, so uterine artery Doppler could be of benefit in these cases. One hundred cases from Kasr Al Ainy Hospital were classified into case and control group. Case group included cases with history of recurrent unexplained abortion. And control group included patients with no history of abortion and one full term child at least. All of them had uterine artery Doppler (Pulsatility Index PI). PI in case group was found elevated compared to control group. From this study, it is beneficial to help those cases by improving uterine receptivity through improving uterine perfusion.