Key Messages of the Iodine Deficiency Working Group (AKJ): Maternal Hypothyroxinemia Due to Iodine Deficiency and Endocrine Disruptors as Risks for Child Neurocognitive Development

Abstract

Iodine deficiency with the resultant maternal hypothyroxinemia and the effects of endocrine disruptors can, individually or together, have a negative effect on embryonic and fetal brain development. This is the conclusion of a recent review by the authors which examined and critically discussed a total of 279 publications from the past 30 years on the effects of mild to moderate iodine deficiency, reduced maternal thyroxine levels, and the influence of endocrine disruptors on child brain development during pregnancy. Adequate iodine intake is important for all women of childbearing age to prevent negative psychological and social consequences for their children. An additional threat to the thyroid hormone system is the ubiquitous exposure to endocrine disruptors, which can increase the impact of maternal iodine deficiency on the neurocognitive development of their offspring. Ensuring an adequate iodine intake is therefore not only crucial for healthy fetal and neonatal development in general, but could also prevent the potential effects of endocrine disruptors. Due to the current deficient iodine status of women of childbearing age and of children and adolescents in Germany and most European countries, urgent measures are needed to improve the iodine intake of the population. Therefore, in the opinion of the AKJ, young women of childbearing age should be instructed to take iodine supplements continuously for at least 3 months before conception and during pregnancy. In addition, detailed strategies for detecting and reducing exposure to endocrine disruptors in accordance with the "precautionary principle" should be urgently developed.

Keywords: endocrine disruptors; hypothyroxinemia; iodine deficiency; neurocognitive development; pregnancy.

Fig. 1

The paradigm shift relating to iodine deficiency (Fig. is based on data from 24 ).

Fig. 2

Changes in thyroid physiology during pregnancy ( a ) and the relationship between thyroid hormone activity and brain development ( b ) (Fig. is based on data from 49 50 ). See text for further explanations (based on data from 2 ).

Abb. 1

Paradigmenwechsel des Jodmangels (Abb. basiert auf Daten aus 24 ).

Abb. 2

Veränderungen in der Schilddrüsenphysiologie während der Schwangerschaft ( a ) und die Beziehung zwischen Schilddrüsenhormonaktivität und Gehirnentwicklung ( b ) (Abb. basiert auf Daten aus 49 50 ). Weitere Erläuterungen siehe Text (nach Daten aus 2 ).