Some prenatal vitamins don't have iodine

BOSTON, Feb. 26 (UPI) -- Boston University Medical Center researchers found only 51 percent of U.S. prenatal multivitamins contain iodine, which could result in iodine deficiency.

"Normal thyroid function in fetuses and breast-fed infants, which is dependent on sufficient intake of iodine, is crucial for a child's normal neurocognitive development," Dr. Elizabeth N. Pearce, an assistant professor of medicine, said in a statement.

"Even mild iodine deficiency may have adverse effects on the cognitive function of children -- the measured iodine content of multivitamins with kelp as the iodine source was extremely variable, and often did not match labeled values, while prenatal multivitamins containing potassium iodine were a more reliable source."

The iodine content of prenatal vitamins is not mandated in the United States, the researchers noted.

The researchers suggest U.S. manufacturers of prenatal vitamins in the U.S. should be encouraged to ensure that their products contain the amount of iodine recommended by the American Thyroid Association and to use only potassium iodine, which contains 76 percent iodine, to maintain consistency in iodine content.

The findings are published in the New England Journal of Medicine.