In European countries with access to iodized salt, pregnant women and women planning a pregnancy should receive an iodine supplements containing approximately 150 μg/day. However, iodine supplementation should be implemented to prevent a development of maternal thyroid failure during pregnancy, iodine intake must be maintained at a safe level. Both iodine deficiency and iodine excess can cause not only maternal thyroid failure but also transient congenital hypothyroidism in infants. In 2007, WHO Technical Consultation first recommended both a low (250 µg/day) and upper (500 µg/day) limit of iodine intake for pregnant and lactating females. Pregnant and breastfeeding women are recommended to take prenatal vitamin-mineral supplements containing iodine in the form of potassium iodide (KI). Kelp and seaweed-based products, because of unacceptable variability in their iodine content, should be avoided. Prenatal supplement manufacturers should be encouraged to include adequate iodine in their products. Professional organizations should influence evolving EU legislation to ensure optimal doses for iodine in prenatal vitamin-mineral supplements.
If iodine deficiency isn’t the cause of hypothyroidism, then iodine supplements provide no benefit. Hashimoto’s thyroiditis, also known as chronic autoimmune hypothyroidism, is the most common cause of hypothyroidism in the United States and is not caused by iodine deficiency. More than adequate or excessive iodine intake may lead to iodine-induced hypothyroidism, autoimmune thyroiditis and may increase the severity of existing autoimmune thyroiditis especially for susceptible populations with recurring thyroid disease, the elderly, fetuses, and neonates. Therefore, if there is anybody who shouldn’t take iodine, it is thyroid patients.