Pathomorphology of gravid endometrium in patients with recurrent miscarriage in early periods with underlying chronic endometritis and the presence of low-functional alleles in folate cycle genes

AIM: This study aimed to identify the peculiarities of pathomorphological alterations in the gravid endometrium and polymorphism of the folate cycle genes in female patients with recurrent early miscarriage and underlying chronic endometritis. MATERIALS AND METHODS: The uterine mucosa of women who had uncomplicated pregnancies and decided to have an artifactual abortion within 5–12 weeks (control group, n = 36) and patients with recurrent miscarriage with underlying chronic endometritis (main group, n = 83) was histologically examined. The polymorphism of the folate cycle genes MTHFR С677Т (rs 1801133), MTHFR A1298C (rs 1801131), and MTRR A66G (rs 1801394) was studied in the female patients of the main group and women with the preserved reproductive function (comparison group, n = 52) through real-time polymerase chain reaction (PCR). RESULTS: Fibroblast-like cells (FLCs) of the stroma sequentially differentiated into predecidual cells from 5 weeks to 12 weeks of uncomplicated pregnancy. In the case of recurrent miscarriage against background chronic endometritis, defect was observed in the differentiation of FLCs of the endometrial stroma. This finding was associated with a decrease in the morphometric parameters of the cells and an increase in the frequency of the occurrence of the low-functional allele 677T in the methylenetetrahydrofolate reductase gene. CONCLUSION: The course and outcome of pregnancy in the first trimester were negatively affected by the structural inadequacy of endometrial stromal cells in recurrent miscarriage and chronic endometritis combined with the presence of the MTHFR 677T allele in a woman's genotype.