This article summarized the actual informations about presence of newly identified short non-coding RNAs, microRNAs, in peripheral blood of pregnant women. On the base of these informations the authors hypothesized that pregnancy complications related to placental insufficiency (preeclampsia and intrauterine growth restriction) could be characterized by unique profile of up-regulated and down-regulated placenta specific microRNAs, which could significantly differ between pregnancy with physiologic and pathologic course.