The FDA is recommending that newborns and children through 3 years old have follow-up thyroid monitoring within 3 weeks after receiving injections of contrast media containing iodine, also called “contrast dye,” for X-rays and other medical imaging procedures.

http://www.fda.gov/safety/medical-product-safety-information/iodine-containing-contrast-media-drug-safety-communication-fda-recommends-thyroid-monitoring-babies