Comparative Assessment of Morphological Features of the Gravid Endometrium in Fetal Loss

BACKGROUND: The use of assisted reproductive technology programs to overcome infertility in some cases continues to be the only way to have a child. Unfortunately, the frequency of reproductive loss reaches average values in the population. Endometrial dysfunction is the cause of the abnormal morphogenesis of the gravid endometrium transformation as a significant factor of reproductive loss in assisted reproductive technology programs and habitual miscarriage. AIM: The aim of this study was to compare the morphological features of aborted fetal tissue in non-developing pregnancies of the first trimester that occurred after the use of assisted reproductive technology and in habitual miscarriage. METHODS: This study was conducted on 97 samples of non-developing pregnancy at 5–8 weeks of gestation. Histological examination was performed using standard methods. Immunohistochemical study to evaluate the expression of progesterone-induced blocking factor, stromal cell-derived factor-1, apoptosis-inducing factor, and endothelial marker was performed according to a standard procedure. Digital microscopy was performed on an Olympus BX46 microscope (Olympus Co., Japan) using cellSens 47 Entry software (Olympus Co., Japan). The expression of markers was calculated using the VideoTesT-Morphology 5.2 program (VideoTesT Ltd., Russia), followed by statistical analysis using the SPSS 23.0 (USA) and GraphPad Prism 9 (USA) software packages. RESULTS: With incomplete gravid transformation of the endometrium, we verified a decrease in the expression of progesterone-induced blocking factor and stromal cell-derived factor-1 in the stroma and glands, and an increase in the expression of apoptosis-inducing factor in the glands. In the endometrial glands with full-fledged gravid transformation after IVF, the expression of progesterone-induced blocking factor was higher compared to non-developing pregnancy with habitual miscarriage. Similar data on the expression of stromal cell-derived factor-1 in the stroma and glands and CD34+ in the stroma of the gravid endometrium were obtained by statistical comparison of markers during full-fledged gravid transformation after IVF and habitual miscarriage. CONCLUSION: A decrease in the expression of progesterone-induced blocking factor and stromal cell-derived factor-1 in the gravid endometrium leads to a loss of local immunosuppression and can cause reproductive loss regardless of the method of pregnancy. An increase in the expression of apoptosis-inducing factor in the glands of the gravid endometrium and CD34+ in the endometrial stroma after IVF and in habitual miscarriage indicate pathological activation of angiogenesis and apoptosis.