Background: Abortion is considered recurrent when it happens spontaneously and successively at least two times. Recurrent pregnancy loss (RPL) can occur due to maternal or fetal factors. Studies recommend that uterine artery perfusion could control endometrial receptivity, and that poor uterine perfusion may be a main cause of unexplained abortion. Objective: The aim of the current study is to investigate the ability of uterine Doppler in assessing uterine causes of RPL.