Iodide Supplements Needed by Pregnant, Nursing Women

Laurie Barclay, MD

May 26, 2014

Pregnant and breast-feeding women should take a supplement with adequate iodide, as recommended by the American Thyroid Association, according to a policy statement from the American Academy of Pediatrics. The statement, published in the June issue of Pediatrics, also recommends that pregnant and lactating women and their infants avoid exposure to excess nitrate, which is typically found in contaminated well water, and thiocyanate from cigarette smoke.

"Many women of reproductive age in the United States are marginally iodine deficient, perhaps because the salt in processed foods is not iodized," write Walter J. Rogan, MD, from the National Institute of Environmental Health Sciences, Research Triangle Park, North Carolina, and colleagues. "Iodine deficiency, per se, can interfere with normal brain development in their offspring; in addition, it increases vulnerability to the effects of certain environmental pollutants, such as nitrate, thiocyanate, and perchlorate. Although pregnant and lactating women should take a supplement containing adequate iodide, only about 15% do so."

The production of thyroid hormone requires adequate iodine intake. Untreated hypothyroidism in infancy may affect cognitive development, and if severe, it may cause serious, permanent brain damage.

Iodized table salt helped prevent iodine deficiency before the main source of salt in the US diet became processed foods, which are not prepared with iodized salt. The prevalence of iodine deficiency has risen along with consumption of processed foods, and about one third of pregnant women in the United States are now iodine-deficient.

Recommendations for Clinicians

  • Pediatricians should be aware of the potential for iodine deficiency among pregnant and breast-feeding women and their infants and counsel them accordingly.

  • Breast-feeding mothers should take a supplement containing at least 150 μg of iodide and should use iodized table salt to achieve a combined daily iodide intake of 290 to 1100 μg.

  • Urine testing for iodine deficiency may be indicated for vegan mothers or for those who do not consume dairy or fish.

  • To avoid potential interference with iodide transport and to prevent methemoglobinemia in their infants, breast-feeding mothers should avoid excess nitrate, which is found in some private well water.

  • Pregnant women should be advised not to smoke and to avoid all exposures to secondhand tobacco smoke, which is a source of thiocyanate exposure.

Recommendations for Government

  • The Environmental Protection Agency should expeditiously complete the regulatory process to establish a national primary drinking water regulation for perchlorate.

  • State and local governments should enact clean air and smoke-free environment ordinances and legislation, especially for environments frequented by children.

"[M]any US women of reproductive age are marginally iodine deficient," the authors conclude. "Women should take a prenatal/lactation supplement with adequate iodide. Such supplements are not currently labeled accurately, but the [US Food and Drug Administration] is moving to correct this situation."

All guidelines authors filed conflict of interest statements with the American Academy of Pediatrics, and any conflicts were resolved through a process approved by the Board of Directors.

Pediatrics. 2014;133:1163-1166.


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