[The influence of iodine deficiency during pregnancy of fetal and neonatal development].

The iodine is fundamental substrate for thyroid hormones synthesis. Thyroxine and triiodothyronine play a crucial role in human brain development and maturation. It is well known, that not only fetal, but also maternal thyroid hormones are essential for normal prenatal central nervous system development. During pregnancy complex changes of maternal thyroid function occur and they are influenced by the maternal iodine supply. With decreasing iodine intake, maternal goiter and hypothyroxinemia as well as fetal and neonatal hypothyroidism become more prevalent. The severity of iodine deficiency and hypothyroidism in the mother during early and midgestation is related to the severity of the neural damage in the fetus. In severe iodine deficiency, central nervous system damage is already irreversible at birth and can only be prevented by correction of the maternal iodine deficiency early in pregnancy. Therefore iodine supplementation during pregnancy is now strongly recommended.