Iodine During Pregnancy Impacts Baby’s IQ: Study

Iodine During Pregnancy Impacts Baby's IQ: Study

As pregnant mothers-to-be, we often obsess over nutrition, balancing our cravings for ice cream and chocolate with more nutrient dense foods like broccoli and kale.

Some women count their fruit and vegetable servings each day, knowing the importance of a healthy diet during pregnancy.

However, despite the healthy food options and fortified food choices so many of us have access to, it seems many pregnant mothers aren’t getting adequate amounts of iodine.

Why is iodine so important?

Iodine is a component of thyroid hormones and thus has an impact on fetal brain development.

Iodine, Pregnancy and Your Baby

Here are five things you need to know about your iodine intake and your baby:

#1: Iodine Plays A Role In Your Baby’s IQ

study published in The Lancet found babies born to mothers with even mild iodine deficiency had lower verbal IQs and reading comprehension scores than babies born to mothers with adequate iodine levels.

As mentioned, iodine plays a role in thyroid function. Your thyroid and hormones have an important part in fetal development. If your iodine levels aren’t adequate then there could be an impact on your baby’s brain development.

The study results showed babies born to mothers with mild to moderate iodine deficiency were more likely to score in the lowest quartile for reading comprehension, reading accuracy and verbal IQ. The scores worsened with lower iodine levels.

#2: Awareness About Iodine Deficiency Is Important

The World Health Organization (WHO) warns about the importance of adequate iodine levels. Their research shows adequate iodine levels are “the single most important preventable cause of brain damage worldwide.”

Many of us have been taught about the importance of adequate folate (or folic acid, in synthetic form) intake. It’s in our prenatal vitamins as well as many fortified foods, and we likely have access to foods that naturally contain it. Find out more about folate.

However, if you ask a pregnant woman about her iodine levels, it’s very likely she’s not aware of the concern.

While we might not be aware of the importance of iodine, recent research and publications are starting to help spread awareness. With most of us having access to a variety of healthy foods and nutrition education, it can be hard to imagine that many of us are deficient in something. Yet many countries, including the US and the UK, report iodine deficiency as a major problem.

#3: Iodine Is Important During The First Trimester

While a baby is quite tiny during the first trimester, it’s the time of important organ and system development. Much like folic acid/folate is important even before a mother knows she is pregnant, iodine levels are important during this phase of development.

#4: Eat Plenty Of Seafood

Healthy fat intake, including Omega 3s, is often what comes to mind when pregnant mothers think of eating fish. We hear about the role of healthy fats in brain development. However, seafood is also a great source of iodine, not just healthy fats. In fact, this study adjusted the research on seafood and Omega 3s and found that seafood intake supported the importance of iodine intake, not just health fat intake.

We might also worry about mercury levels. We might cut our seafood intake to much lower than prior to our pregnancy thinking we are protecting our babies from mercury, but this might have a negative impact on their brain development. The key to avoiding mercury isn’t simply avoiding fish but rather choosing seafood low in mercury such as salmon, herring and shrimp which will provide us with iodine.

#5: Be Cautious With Supplements

Some countries have national salt-iodization programs but this isn’t something adopted by the UK. For UK residents, and those in other countries without this program, iodine intake becomes solely a personal responsibility – a difficult task for some given the lack of awareness.

Prenatal vitamins containing iodine can be an important part of ensuring pregnant mothers receive iodine. However, unregulated supplements, like kelp, might be well marketed but could provide little or unreliable levels of iodine.

Be sure to speak with your maternity care provider as well as a provider familiar with supplements, before choosing to take anything.

What Does This Mean For Me?

Being pregnant can sometimes feel like a scary responsibility. We are housing a growing baby and feel responsible for the development of each and every part. Knowing your diet can impact your baby’s cognitive ability can feel overwhelming at times.

When we read information from studies it can be difficult to process. However, it’s important to remember this information is available to help care providers better inform pregnant mothers, and for pregnant mothers to make informed choices – not to make us overly worried.

Last Updated: September 20, 2015


Maria Silver Pyanov is the mom of four energetic boys, a doula, and a childbirth educator. She is an advocate for birth options, and adequate prenatal care and support. She believes in the importance of rebuilding the village so no parent feels unsupported.

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