Iodine is an indispensable nutrient for the human body. When the intake is insufficient, the body will experience a series of disorders. Iodine deficiency disease is the damage to the human body caused by iodine deficiency in the natural environment, which can manifest as the formation of various diseases. Endemic goiter, endemic cretinism, endemic subclinical cretinism, and diseases that affect fertility such as infertility, premature babies, stillbirths, and congenital malformations are collectively referred to as "iodine deficiency disease." Iodine is an essential component of thyroid hormone. The thyroid gland uses iodine and tyrosine to synthesize thyroid hormones. Therefore, when iodine intake is insufficient, the body will experience a series of disorders. Due to the different degrees and periods of iodine deficiency in the body, the severity of the disorders in the body is also different.