Thyroid function in pregnant women with mild iodine deficiency

Abstract

The study whose purpose was to examine the time course of changes in the function of thyroid gland (TG) in pregnant women with mild iodine deficiency enrolled 218 females in different periods of pregnancy in accordance with the following criteria: the absence of dysfunction (of TG). In 128 patients of them, baseline TG pathology was absent; 90 patients were found to have these or those types of euthyroid goiter. Some women received iodine preventive therapy (150-200 mcg of potassium iodide daily) on an individual basis. Comparison of the levels of TTH and T4 in women receiving and no receiving iodine preventive therapy revealed that by the end of pregnancy, those receiving 150-200 pg of potassium iodide had significantly lower TTN levels and higher T4 levels. Comparing the time course of changes in the volume of TG between these groups showed that they did not increase to a significantly greater extent in the females receiving no iodine preventive therapy. Whether potassium iodide was used, there were no changes in the size of TG nodal masses during pregnancy. In the control group, active smokers were fewer than those in the goiter group (p = 0.035). Six-ten months after labor, the volume of TG further increased in the females without iodine preventive therapy group while that substantially decreased in those receiving 150-200 pg of iodine daily. It is concluded that pregnancy in the presence of mild iodine deficiency is accompanied by a higher risk of the development and progression of goiter, and by a risk for gestational hypothyroxinemia, which is prevented by an individual iodine preventive therapy with 150-200 pg of potassium iodide daily. Furthermore, pregnancy is not accompanied by a risk of increases in the size of nodal euthyroid colloid goiter that does not itself entail an additional risk for gestational hypothyroxinemia.