Pathogenetic aspects of placental disorders in pregnant women with iodine deficiency diseases based on the study of morphological and immunohistochemical features of the placenta

Backgraund: The presence of iodine-deficient thyroid disease in combination with the «carriage» of specific autoantibodies is associated with an increased risk of developing obstetric and perinatal complications due to placental disorders, but the pathogenetic mechanisms of this process remain insufficiently studied. The relevance of the study is due to the high prevalence of this pathology and the need to optimize strategies for reducing perinatal complications by identifying the key links in the pathogenesis. Objective. To study the pathomorphological and immunohistochemical features of the placenta, including the expression of HLA-DR in the decidual tissue, amniotic membrane, and villus stroma, in order to identify the pathogenic mechanisms of placental disorders in women with iodine-deficient thyroid diseases. Material and methods. A prospective controlled comparative study was conducted, which included the participation of 41 women. The main group included 21 women with iodine deficiency disease, the control group included 20 patients without thyroid pathology. The main group is further divided into the first group - patients with iodine deficiency disease and the absence of antibodies to thyroid tissue (n=9), the second group - pregnant women with iodine deficiency disease and the presence of antibodies to thyroid tissue (n=12). The study included a clinical and anamnestic analysis of the main characteristics of the examined women, an assessment of the newborns’ condition, a morphological analysis of the afterbirths, and a quantitative assessment of the expression of the HLA-DR II α chain in B-lymphocytes using the immunohistochemical method. The data were processed in Microsoft Excel and SPSS Statistics 7.0 programs with the calculation of the Mann-Whitney criteria and the exact one-sided Fisher method with the Bonferroni correction. Results. Women with thyroid disorders (especially those with autoantibodies) were more likely to experience pregnancy loss (38.1% and 10.0%, respectively; p=0.015), placental disorders (38.1% and 5.0%; p=0.013), and gestational diabetes (47.6% and 5.0%; p=0.002). Women with thyroid disorders were more likely to have induced deliveries (71.4% and 15.0%, respectively; p=0.0003). The most common complications were weak labor, which was more common in women with antibodies to thyroid tissue (25.0% and 0.0%; p=0.044), and low birth weight (23.8% and 0%; p=0.027). Newborns from mothers with iodine deficiency had a lower Apgar score (p=0.038) and a high incidence of hypoxic-ischemic encephalopathy (66.7%, p=0.043), especially in mothers with autoantibodies (75%, p=0.014). Histological analysis of the main group’s placentas revealed signs of impaired angiogenesis. Immunohistochemical analysis revealed higher HLA-DR I expression. Conclusions. In areas of the region with iodine deficiency, there is an increase in autoimmune and iodine-deficient conditions, which requires a comprehensive approach starting from the preconception stage. The study revealed a correlation between immune and endocrine disorders that affect women’s reproductive health and lead to obstetric complications, even in cases of asymptomatic carriage of autoantibodies.