Despite the continuous improvement in health technology and the quality of obstetric and gynecological care, the occurrence of reproductive failures has not tended to decrease in number. The aim of the study is to identify prognostic criteria for the loss of a fetus. Material and methods. The study included 135 patients with fetal loss syndrome (FLS) and 137 patients who gave birth to healthy, full-term babies. A standard clinical and laboratory examination was carried out in which attention was paid to the particularities of the individual, family, and obstetric histories. The presence of thrombogenic mutations and polymorphisms of the folate cycle genes (MTHFR, MTRR, MTR) and the plasminogen activator inhibitor gene (PAI-1) was determined using real-time polymerase chain reaction. A study of the hormonal function of the trophoblast and the morphological study of the chorion (placenta) were carried out. Results. It has been established that when predicting the recurrence of fetal loss syndrome, it is necessary to carry out an assessment of the family, individual, and obstetric and gynecological histories. Relapse of the syndrome can occur when 3 or more of the thrombogenic polymorphisms of the folate cycle genes and the PAI-1 gene are combined with aggravating anamnestic familial, reproductive and general health factors. Conclusion. A personalized approach to managing the treatment of women with fetal loss syndrome, incorporating a complete medical examination, including the determination of the polymorphism of the folate cycle genes and the PAI-1 gene, is advised.