Iodine intake and thyroid function during pregnancy

Iodine is an essential micronutrient for pregnant women, which affects thyroid function of pregnant women and fetus, and thus influences the intellectual development of offspring. Severe iodine deficiency could lead to overt hypothyroidism and fetal cretinism. In the areas implemented the universal salt iodization (USI) program, mild to moderate iodine deficiency and iodine excess may coexist during pregnancy. Iodine deficiency could lead to hypothyroxinemia in pregnant women. Iodine more than adequate and iodine excess could increase the prevalence of subclinical hypothyroidism. The effect of iodine supplementation on thyroid function in pregnant women with mild to moderate iodine deficiency may result in different conclusion. Therefore, it is important to maintain optimal urinary iodine concentration to prevent thyroid dysfunction. Key words: Pregnancy; Iodine nutrition; Thyroid function