Background:The predominant part of IVF cycles results in embryo transfer, but only about one third of all cycles reach clinically achieved pregnancy. This is evidence that most embryos failed in an early stage of pregnancy achievement. Recurrent implantation failure after IVF procedures emphasize the clinical importance of this crucial step in assisted reproductive technology. Repeated unsuccessful IVF attempts force efforts to investigate the firm mechanism of the implantation and to find approach to increase pregnancy outcome success. Plenty of factors have been recognized to affect either success, or failure rate of IVF embryo transfer. Maternal side factors include age, parity, hormonal levels before stimulation, antral follicles count, endometrial thickness and quality of transformed endometrium. Other factors, having functions in coagulation and fibrinolysis cascades, were found to be connected with the transformation processes in the endometrium during the implantation.