Iodine is an important raw material for the synthesis of thyroid hormone by the human thyroid gland, and thyroid hormone plays an extremely important role in the activities of various organs and systems of the human body, especially for the growth and development of the nerve center and the intellectual development of the body has a decisive role. Feng Zhihai, Department of Endocrinology, The First Affiliated Hospital of Henan College of Traditional Chinese Medicine, the development of the nervous system of the fetus before the sixth month of gestational age, mainly relying on the mother’s thyroxine and iodine passed through the placenta to the fetus. After 6 months of gestation, the thyroid gland of the fetus is able to secrete thyroid hormone, which requires iodine from the mother. Therefore, it is very important for the neurological and intellectual development of the fetus for the mother to ensure adequate iodine intake throughout pregnancy. Dietary iodine supplementation is a simple and effective way to get enough iodine by eating seafood regularly. However, it should be noted that excessive iodine intake is not only not beneficial to the fetus, but also harmful, so it is unnecessary to take highly iodized food.