[Iodine deficiency during pregnancy].

Iodine deficiency during pregnancy. Iodine is a necessary element to thyroid hormones synthesis, and is essential in neurological development. Iodine needs increases during pregnancy. In developed countries, iodine deficiency is the second cause of mental delay avoidable after foetal alcoholization syndrome. In France, there is a moderate iodine deficiency, according to World Health Organization (WHO) thresholds. The marker used in studies is 24h urinary iodine excretion, but this marker is not applicable at the individual level. European substitution policy is hard to establish considering alimentary customs for each population. Salt fortification has a limited impact because its use has to be limited during pregnancy. Prophylaxis is recommended systematically by WHO in moderate deficiency areas like in France: 150 μg/ day for women of childbearing-age and 250 μg/ day during pregnancy and breast feeding. Side effects may seem bearable considering benefit/ risk ratio providing not exceeding 500 μg/day.