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.
The daily iodine intake varies widely throughout the world. US iodized salt contains 46–77 ppm (parts per million), whereas in the UK the iodine content of iodized salt is recommended to be 10–22 ppm. Table salt in Italy is iodized at 30 ppm, which is typical of many European programs. Although iodine consumption is generally lower in Europe, the people in these countries do not usually develop thyroid disease. However, when people with past or present thyroid abnormalities are exposed to unaccustomed, large amounts of iodine (such as moving to North America and increasing their iodine intake), they can develop thyroid disease.