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Pregnant women should take an iodide-containing supplement to protect the brain development of their babies, according to the leading US group of paediatricians.
Iodine, which the body can get from iodide, is needed to make the thyroid hormones that are required for children's brain development before and after birth.
"Women who are childbearing age need to pay attention to this topic as well, because about half of the pregnancies in the US are unplanned," Dr Jerome Paulson said. "Women in the early part of the pregnancy may not realise they're pregnant."
Marginal deficiency
Paulson is the chairperson of the American Academy of Paediatrics Council on Environmental Health, which authored the policy statement. He is also a paediatrician at Children's National Medical Centre in Washington, DC.
The recommendations were published in the journal Paediatrics.
People typically get the iodine they need from table salt, which in the US is fortified with iodide. Eating processed foods exposes Americans to salt that is not iodised, however.
The Council writes that past research has suggested that about one-third of pregnant women in the US are marginally iodine deficient. Also, only about 15% of women take a supplement containing an adequate amount of iodide.
The American Thyroid Association and the National Academy of Sciences suggest pregnant and breastfeeding women get 290 micrograms of iodide per day.
Women may need to take a supplement with 150 micrograms of iodide to reach that recommended level, but most prenatal and lactation vitamins contain less, according to the Council.
"Breastfeeding mothers should take a supplement that includes at least 150 micrograms of iodide and use iodized table salt," the Council writes.
Iodine is critical
Additionally, the Council says women may need to be tested for iodine deficiency if they are vegan or don't eat fish.
"Obviously iodine is critical to the foetal and child brain," Dr Loralei Thornburg said. "Therefore having a diet that's rich in iodine is critical."
Thornburg was not involved in making the new recommendation. She is a high-risk pregnancy expert at the University of Rochester Medical Centre in New York.
"Although many women are largely iodine deficient, most women do get iodine in the (form) of food," she told Reuters Health. "This isn't something women should freak out about just yet."
Thornburg said the ideal amount of iodide supplementation depends on how much of the compound women already get from their diets.
The Council says a pregnant or lactating woman's combined iodide intake should be between 290 and 1100 micrograms per day. Specifically, it should be in the form of potassium iodide.
"This is something that's fairly routine," Paulson said. "I think what we're saying is people need to pay attention to the details of what they're doing, but not radically change their behaviour."
Nitrate should be avoided
The authors also suggest pregnant or lactating women avoid nitrate, found in contaminated well water, and thiocyanate, which is usually found in cigarette smoke and certain vegetables like broccoli, cauliflower and cabbage. The two chemicals can disrupt the ability of iodine to be processed into hormones. However, women rarely eat enough of the vegetables for thiocyanate levels from those sources to be concerning, they note.
Finally, the Council recommends that the US Environmental Protection Agency proceed with appropriate regulation of perchlorate in waterways. Perchlorate, which is a chemical used in rocket fuels and explosives, can disrupt the body's use of iodine to make thyroid hormones.
"I think people can have some control over their exposure to tobacco smoke, but they may not even be aware of the perchlorate or other chemicals in the water," Paulson said.
The Council also writes that there is some inconsistency between the iodide on the label of supplements and their actual content. The US Food and Drug Administration should "do what is necessary to allow consumers to identify and use iodide supplements with confidence" if the industry's actions are insufficient, it adds.
Read more:
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Potassium iodide recommended dosage
17 quick facts about potassium iodide
