Assessment of thyroid function, ioduria and oxidative stress in women in the first trimester of pregnancy

Abstract

Introduction: adequate iodine intake during pregnancy is essential for the synthesis of thyroid hormones, which are important for the physiological functions of the mother and appropriate maturation of the central nervous system of the fetus. Objective: the objective of the present study was to determine the levels of urinary iodine excretion and thyroid function, antioxidants and oxidative stress markers in pregnant women. Methods: the study was conducted on 191 pregnant women and 62 non-pregnant women who were evaluated regarding nutritional status. Analyses of urinary iodine, of oxidative stress markers and thyroid function were performed, revealing iodine insufficiency in 81 pregnant women. Results: there was no change in the thyroid stimulating hormone concentration in 89% of the pregnant women. Antithyroperoxidase antibody values were higher in the control group compared to the pregnant women’s group (64.5% and 12.6%, respectively) and antithyroglobulin antibody values were also higher in the control group (11.6%). Assessment of oxidative stress revealed higher levels of advanced oxidation protein products, of total antioxidant capacity and of superoxide dismutase antioxidants in pregnant women. Classification of ioduria with respect to oxidative stress markers revealed lower α-tocopherol levels for the pregnant women with iodine insufficiency. Conclusion: on this basis, the results suggest that iodine insufficiency did not induce changes in thyroid stimulating hormone levels or antibodies and those pregnant women with adequate urinary iodine excretion had a better profile of the α-tocopherol antioxidant, indicating that iodine may play a significant role in antioxidant capacity during gestation.