It is well established that moderate to severe iodine deficiency during pregnancy can impair neurological development of the fetus.

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Normally, you’re recommended to consume about 150 μg of iodine per day. But when you are pregnant, your body needs a lot more.

Iodine is a vital part of making thyroid hormones, which are crucial for proper brain and neurological development during gestation. These iodine benefits are particularly important during early pregnancy (the first trimester)._[1-3] Studies show that children of iodine-deficient mothers tend to show lower cognitive function.

Iodine Requirement Increases by 50% During Pregnancy

Because of this, the iodine requirement for a woman increases by at least 50% during pregnancy._[1] Pregnant women are advised to consume at least 250 μg per day, compared to the normal 150 μg per day._[4]

Iodine Deficiency During Pregnancy Can Lead to Cognitive Impairments in the Child

It is well established that moderate to severe iodine deficiency during pregnancy can impair neurological development of the fetus. Severe deficiency can lead to extreme developmental problems like cretinism, a condition of severely delayed and impaired  physical and mental growth._[1,2]

What is less known is that mild iodine deficiency during pregnancy can be very dangerous too._[1] A large study on over 1000 pregnant women was published in the journal Lancet in 2013. Children of women who had urinary levels of iodine less than 150 μg/g (considered mildly deficient) were more likely to have scores in the lowest quartile for verbal IQ, reading accuracy, and reading comprehension compared to those with levels above 150 μg/g. The farther iodine levels dropped below 150 μg/g, the worse the scores became._[2]

Another study used a nine-year follow up period after pregnancy to assess academic performance in children. They found that children of mothers with iodine levels less than 150 μg/g showed reductions in scores of 10% in spelling, 7.6% in grammar, and 5.7% in English literacy._[5] These results of these studies show that moderate deficiency can result in less severe, but still significant, impacts on brain development and cognition.

Be Sure to Get Enough Iodine

Unfortunately, many women don’t get enough iodine during pregnancy._[6] A study published in August 2015 on Swedish women found that the median iodine level of the 459 women was only 98 μg/g, far below the recommended 150 to 250 μg/g._[1]

Pregnant and lactating women should consume 250 μg of iodine per day. Anywhere between 250 μg to 500 μg is considered more than adequate, and over 500 μg is excessive. The minimum daily requirement is 150 μg per day._[4]

Women are recommended to use iodized salt, and to take a supplement that contains 150 μg iodine._[6] Talk with your doctor about how to safely get enough iodine into your daily diet to be sure you are helping your baby form a healthy brain.

For more tips on having a healthy pregnancy, read these articles:

• Yoga Found Effective for Pregnancy Anxiety
• The Benefits of Working Out While Pregnant: How to Prevent Gestational Diabetes and Weight Gain
• Natural Tips for Recovering from C-Section Surgery

Share Your Experience

Did you take iodine during pregnancy? If so, how much? Have you ever been iodine deficient? Share your thoughts in the comments section below.

This article was originally published in 2015. It is regularly updated.

[1] Acta Obstet Gynecol Scand. 2015 Aug 20. [Epub ahead of print]

[2] Lancet. 2013 Jul 27;382(9889):331-7.

[3] J Trace Elem Med Biol. 2013 Jul;27(3):174-83.

[4] Paediatr Perinat Epidemiol. 2012 Jul;26 Suppl 1:108-17.

[5] J Clin Endocrinol Metab. 2013 May;98(5):1954-62.

[6] J Clin Endocrinol Metab. 2008 Jul; 93(7): 2466–2468.