An iodine deficiency produces compensatory hypertrophy of the thyroid gland, resulting in a goiter. Cretinism is a consequence of severe iodine deficiency in early pregnancy. Cretins are feeble-minded dwarfs with characteristic faces and gait. Mild to moderate maternal deficiency during pregnancy causes lesser degrees of neurological damage, particularly poorer cognitive performance and hearing impairment. Initially, goiters are soft and diffuse but become fibrotic in older individuals.
Nodular goiters are a common result of maternal iodine deficiency.
Thyroxine deficiency in adults results in hypothyroidism characterized by a low metabolic rate. Potassium iodate is used more frequently as it has the advantage of being stable in crude moist salt even under unfavorable conditions. Bread and water are alternate vehicles for iodine. Goiters that have not become fibrotic disappear when iodine is given in any of the forms described above. If a goiter appears during pregnancy, treatment will be too late to avoid damage to the fetus.