The miRNAs produced predominantly in the placenta are probably involved in placental differentiation and maintenance of pregnancy. One of the important functions of miR-126 is its involvement in angiogenesis by enhancing the expression of VEGF. Abnormalities of placental vasculature may result in several gestational complications, including pregnancy loss. The current study compared the expression of miR-126 in the plasma of women with recurrent miscarriages and women with healthy pregnancies by Realtime qRT-PCR. The results indicated that the expression difference of miR-21 between the pregnant patients and the controls was statistically significant (p =0.002). This microRNA can be used as a biomarker in diagnosis and progression.