They regulate gene expression, infl uence apoptosis, inhibition or stimulation of protein synthesis, regulation of the cell cycle etc. <...> The article presents the literature data and the position of the authors on the possibility of using them as prognostic markers in obstetric practice. <...> So a great deal of attention is diverted to studying the subtle mechanism of development of pathology on a molecular level, determining of early markers with the aim of isolating 74 «Reproductive health. <...> As of today the study of a new class of markers – micro RNA seems like quite an interesting, fruitful, little researched and contradictory subject of many studies especially its aspects that have to do with obstetric complications and the ability to predict the future illnesses of the child and adult. <...> They describe the clinical importance of just a few dozen micro RNAs. <...> MicroRNA – is a class of small non-coding RNA molecules that are about 22(18–24) nucleotides in length, that were discovered in 1992 by Victor Ambrose, Rosalind Lee and Ronda Feinbaum during their study of the lin14 gene in the development of Caenorhabditis elegans [1]. <...> MicroRNA participates in all biological processes from conception to growth and development to aging and death, in the development of pathology in adaptation to stress. <...> But because of little studied mechanisms of the action of entire class of microRNA they have been called “dark matter of biology” [5]. <...> It has to do with their functions: regulation of gene expression, eff ect on apoptosis, suppression and stimulation of protein synthesis, regulation of cell cycle etc. <...> MicroRNA regulates the expression of cell genes on a post-transcription level by suppressing the translation of protein coding genes. <...> Each separate molecule regulates a separate cascade of genes, by activating expression of one type of genes and suppressing the expression of other types. <...> This facilitates their diff erent functions on a cellular level, for instance micro RNA-21 plays a part in blocking apoptosis, angiogenesis as well as the development of fi brosis [1, 5]. <...> Disturbances in the process of expression of microRNA, that lead to an increase or decrease of levels of particular types of microRNA, or the presence of polymorphism in the area of binding microRNA with mRNAtarget may be a reason for various pathological states and can accompany them. <...> Some micro RNA by way of being actively released or passively transported <...>