过去,人们经常错误的认为食物中碘缺乏所造成的最主要,最严重的后果是甲状腺肿大。现在已确认神经系统的损害是地方性碘缺乏最严重的后果。这是由于在胚胎及新生儿期,即神经系统发育的关键时期,神经组织分化和成熟依赖于足量甲状腺激素存在的缘故。而且,在妊娠早期胎儿甲状腺未形成之前,从母亲运至胎儿的甲状腺激素是胎儿甲状腺激素的主要来源。在严重碘缺乏地区,母亲血清甲状腺激素水平降低,结果导致临床上出现地方性克 In the past, people often mistakenly thought that the most important and serious consequence of iodine deficiency in food was goiter. It has now been confirmed that the damage to the nervous system is the most serious consequence of endemic iodine deficiency. This is due to the fact that the differentiation and maturation of neural tissue are dependent on the presence of sufficient amounts of thyroid hormones during embryonic and neonatal periods, a critical period of the development of the nervous system. Moreover, thyroid hormones delivered from mother to fetus are the major source of fetal thyroid hormones before the fetal thyroid gland is formed in early gestation. In severe iodine deficiency areas, maternal serum thyroid hormone levels decreased, resulting in the clinical emergence of local grams