Reduced Iodine Intake and Iodine Prophylaxis in Pregnancy: Importance of Hypothyroxinemia in the First Trimester of Gestation

Abstract:

The term "hypothyroxinemia" means that whether or not clinical or subclinical hypothyroidism are presented, serum free T4 (FT4) values are low compared with values usually found at the same stage of pregnancy in normal women with an adequate iodine intake. This kind of anomaly had created concern in developed countries, especially in western Europe. Maternal hypothyroxinemia induced by an iodine intake that fails to meet the increased needs imposed by the fetus, is likely to be much more frequent than primary thyroid failure and thyroid autoimmune diseases. Third trimester or early postnatal correction of low circulating T4, a measure quite effective in preventing most CNS damage in congenital hypothyroidism, does not reverse the deficit caused by maternal hypothyroxinemia, since most of the consequences become permanent by the end of the second trimester. Prevention of hypothyroxinemia requires correct iodine intake. Different approaches exist, such as consumption of iodized salt-administration of potassium iodine and multivitamin pills containing iodine could also be considered, especially when restriction of salt consumption is recommended. Hypothyroxinemia diagnosed during pregnancy should be treated immediately with administration of levothyroxine. Caution is necessary to avoid excess iodine in the fetal thyroid. © 2009 Elsevier Inc. All rights reserved..

Año de publicación:

2009

Keywords:

Fuente:

scopus