Iodine is a trace element that is important for the synthesis of thyroid hormones.
During pregnancy, iodine requirements are increased by approximately 50% because of
physiological changes. Adequate iodine status in pregnancy is crucial for maternal
health and fetal growth. The World Health Organization (WHO) recommends a daily intake
of 250g iodine for pregnant women to maintain adequate iodine status. Severe iodine
deficiency during pregnancy can result in a series of detrimental effects on maternal
and fetal health including hypothyroidism, goiter, stillbirth, abortion, increased
neonatal mortality, neurological damage, and intellectual impairment. Correction of
severe iodine deficiency can reduce the risk of adverse impacts. However, the influences
of mild-to-moderate maternal iodine deficiency on fetal neural development and cognitive
function are less clear. The safety and efficacy of iodine supplementation in mildly-to-moderately
iodine-deficient women also remain uncertain. In addition, excess iodine during pregnancy
carries a risk of adverse effects, and the recommended safe upper limits of iodine
intake are controversial. Effective iodine supplementation should be implemented,
and routine monitoring is necessary to guarantee adequate iodine status.