%0 Journal Article
%T Do Thyroid Disrupting Chemicals Influence Foetal Development during Pregnancy?
%A Marie-Louise Hartoft-Nielsen
%A Malene Boas
%A Sofie Bliddal
%A £¿ase Krogh Rasmussen
%A Katharina Main
%A Ulla Feldt-Rasmussen
%J Journal of Thyroid Research
%D 2011
%I Hindawi Publishing Corporation
%R 10.4061/2011/342189
%X Maternal euthyroidism during pregnancy is crucial for normal development and, in particular, neurodevelopment of the foetus. Up to 3.5 percent of pregnant women suffer from hypothyroidism. Industrial use of various chemicals¡ªendocrine disrupting chemicals (EDCs)¡ªhas been shown to cause almost constant exposure of humans with possible harmful influence on health and hormone regulation. EDCs may affect thyroid hormone homeostasis by different mechanisms, and though the effect of each chemical seems scarce, the added effects may cause inappropriate consequences on, for example, foetal neurodevelopment. This paper focuses on thyroid hormone influence on foetal development in relation to the chemicals suspected of thyroid disrupting properties with possible interactions with maternal thyroid homeostasis. Knowledge of the effects is expected to impact the general debate on the use of these chemicals. However, more studies are needed to elucidate the issue, since human studies are scarce. 1. Introduction Maintaining maternal euthyroidism during pregnancy is important for growth and development, in particular neurodevelopment of the foetus. Even subtle changes in thyroid function of the pregnant woman can cause detrimental effects for the foetus [1¨C5]. In the first trimester, the foetus relies solely on the thyroid hormones thyroxine (T4) and tri-iodothyronine (T3) and iodine from the mother. Later in pregnancy and during lactation, maternal thyroid hormones still contribute significantly to foetal thyroid homeostasis [6¨C8]. Worldwide, both overt and subclinical hypothyroidism are frequent among fertile women [9¨C14]. Prior maternal thyroid diseases as well as iodine and selenium deficiencies are known risk factors for hypothyroidism. Abundant industrial and household use of various chemicals¡ªcalled endocrine disrupting chemicals (EDCs)¡ªexpose humans with potential harmful influences on health and hormone regulation. As recently reviewed, several of these EDCs have been found to have thyroid disrupting properties as well [15¨C17]. Probably each chemical has limited thyroid disruptive effects at environmental exposure doses. However, the combined influence of several chemicals through different pathways of thyroid hormone synthesis and action may have significant impact on both maternal and foetal thyroid function [18, 19] and, thus, a potential to compromise foetal development and maturation. This paper will focus on the influence of thyroid hormones on foetal development in relation to the chemicals suspected to have thyroid disrupting properties. Knowledge on
%U http://www.hindawi.com/journals/jtr/2011/342189/