Trying to Get Pregnant? Why Iodine Can Help

by Mary Shomon Patient Advocate

When you're in babymaking or breastfeeding mode, you pay a lot of attention to your nutrition. But even though you're on top of your diet and take your prenatal vitamins, there's a chance you may be overlooking one crucial nutrient: iodine. Getting enough is not only important for your own health, but your baby's as well.

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Iodine Is an Essential Nutrient

Iodine is a mineral you get from food, iodized salt, and supplements. You need sufficient levels to produce thyroid hormone and avoid hypothyroidism—an underactive thyroid. Thyroid hormones are essential to every bodily function. We're talking everything from breathing and heart rate to body weight and muscle strength. When levels are too low, you may have trouble sleeping and focusing, and you may even experience depression along with joint or muscle pain. Women may also have more frequent, heavier periods, too.

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How Common Is Iodine Deficiency?

Studies report that around 30% of American women of childbearing age are deficient in iodine; and up to one-half have suboptimal iodine levels during pregnancy.

You are at increased risk of iodine deficiency if:

  • You are a vegan.
  • You are allergic to or restrict your intake of iodine-rich dairy products and/or seafood.
  • You don’t take supplemental iodine.
  • You take a prenatal vitamin that doesn’t include iodine.
  • You smoke
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Can You Get Tested for Iodine Deficiency?

Testing iodine levels requires a urinary iodine clearance (UIC) test, but getting these tests isn’t super common.

“Obstetricians do not routinely check for iodine deficiency in pregnancy, but we do check for abnormal thyroid function,” says Meena Garcia, M.D., an assistant professor of obstetrics and gynecology (OB/GYN) at Columbia University Medical Center and division chief of OB/GYN at New York-Presbyterian Medical Group.

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How Much Iodine Do You Need Per Day?

So without knowing your exact levels, how can you get adequate iodine? Thankfully, there are guidelines in place for that! According to the National Institutes of Health, your recommended daily intake of iodine is:

  • During preconception: 150 mcg
  • During pregnancy: 220 mcg
  • During breastfeeding: 290 mcg
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Iodine and Conception

You need healthy iodine levels to become pregnant and to sustain a healthy pregnancy. Iodine deficiency can actually make it harder to get pregnant in the first place. For example, even moderate iodine deficiency is linked to an almost 46% reduced chance of becoming pregnant each cycle, and it increases your risk of miscarriage. While that sounds scary, ensuring adequate intake mitigates the risk. You've got options!

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Iodine During Pregnancy

During pregnancy, you need about 50% more iodine. It’s especially important during the first trimester, when your baby’s thyroid gland is developing and still unable to produce thyroid hormone, which is needed for normal brain development, according to researchers from Boston Medical Center. Getting this extra iodine can also help your child avoid later problems with reading comprehension, executive function (things like goal-setting), and impaired language skills.

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Iodine When Breastfeeding

When you’re exclusively breastfeeding, your baby’s intake of much-needed iodine comes only from your diet (just like the rest of his nutrition). This means that a breastfeeding mother needs to pay particular attention to getting adequate iodine, because if you are deficient, then your baby is at a higher risk of iodine deficiency as well.

Getting Iodine From Food

Thankfully, it’s not hard to incorporate iodine-rich foods into your daily diet. “We recommend patients eat a wide variety of fresh vegetables and fruits, seafood, dairy, and eggs, which are good sources of iodine,” says Dr. Garcia. “We also recommend preferentially using iodized salt in cooking.”

Other iodine-rich foods include seaweeds such as kelp, nori, kombu, and wakame, and grain products, such as bread, fortified pasta, and cereal.

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Iodized Salt and Iodine Deficiency

If you’re looking to get your iodine from salt, though, there are a few key things to know. In recent years, there has been an increase in the number of iodine-deficient women, and part of the reason may be due to an increase in the use of specialty salts, says Dr. Garcia. Yep, that fancy pink salt in your pantry probably doesn’t have much iodine in it.

“Unfortified specialty salt such as sea salt does not naturally contain much iodine,” adds Angela Leung, M.D., an assistant professor of medicine and endocrinologist at the UCLA David Geffen School of Medicine. Other types of salt that have little to no iodine include rock salt, kosher salt, and Himalayan salt.

What About an Iodine Supplement?

If iodine is so important, should you take it in supplement form, too? Yep: Many experts, including Dr. Garcia, recommend you start taking iodine as early as three months before trying to conceive, and continue taking it through breastfeeding.

Look for a supplement that will give you 150 mcg of iodine during this time, says Dr. Leung, whether that’s through your prenatal vitamin or a separate vitamin. “Make sure you buy one with the right amount of iodine, because not all the prenatals on the market have it,” says Dr. Leung.

Your Breastfed or Formula-Fed Baby’s Iodine Needs

The National Institutes of Health (NIH) recommends babies get 110 mcg of iodine daily from birth to age 6 months, the period when only breastmilk or formula is recommended.

Infant formula is required to have added iodine, according to Dr. Weydert. But if your baby is exclusively breastfed, it’s especially important that you get adequate amounts of iodine from your diet and iodine supplementation. “Iodine supplementation of breastfeeding women can significantly improve iodine supply to the infant,” says Dr. Weydert.

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Iodine Deficiency During Weaning

From 7 to 12 months of age, the recommended intake of iodine, according to the NIH, is 130 mcg daily.

A 2019 study in Thyroid, co-authored by Dr. Leung, reported that as babies are weaning—getting less breastmilk or formula and more solid food—the rate of iodine deficiency in the babies increases. The reason? The iodine content of commercial baby food is not regulated, and iodized salt is typically not added to home-cooked and commercial baby food.

Best Foods With Iodine for Weaning Babies

As you introduce solid foods to your baby, “This is an opportunity to include foods that are rich in iodine,” says Dr. Weydert.

Some common food sources of iodine for weaning babies include:

  • Macaroni: 1 cup of enriched macaroni has 27 mcg iodine.
  • Eggs: 1 large egg has 24 mcg iodine.
  • Bread: 2 slices of enriched white bread have 45 mcg iodine.

If you are feeding your baby home-cooked food, you can also prepare it with iodized salt. A quarter teaspoon of iodized salt has around 71 mcg of iodine.

Iodine for Toddlers

Toddlers aged 1-3 should get 90 mcg of iodine daily from food sources, says the NIH.

While pediatricians typically do not recommend cow’s milk to infants under age 12 months, after that age, “if a parent wants to offer cow’s milk products, this also can be a good source of iodine,” says Dr. Weydert. One cup of plain, low-fat yogurt has 75 mcg of iodine, and one cup of reduced-fat milk has 56 mcg.

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The Importance of Iron-Rich Foods

An added factor that may aggravate low iodine intakes in weaning infants is the high prevalence of iron deficiency in babies.

“Iron deficiency can impair production of thyroid hormone,” explains Dr. Weydert. “Making sure that the diet is also rich in iron-fortified cereals, meat, eggs, beans, fish, raisins, [and more] may help improve both iron and iodine levels.”

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Can You Get Too Much Iodine?

While iodine is a vital part of a healthy diet for you and your baby, you should also avoid consuming too much iodine.

“There are reports in the literature of infants developing thyroid disorders from excessive iodine exposure in breastmilk,” says Dr. Weydert. “This was typically caused by the mother taking high levels of iodine supplements or exposure to topical iodine. It’s not likely an infant could get too much iodine from diet alone.” Stick to the 150 mcg supplement per day for yourself, but Dr. Weydert cautions against iodine supplements for infants on well-balanced diets, due to toxicity concerns.

Mary Shomon
Meet Our Writer
Mary Shomon

Mary Shomon is a patient advocate and New York Times bestselling author who empowers readers with information on thyroid and autoimmune disease, diabetes, weight loss and hormonal health from an integrative perspective. Mary has been a leading force advocating for more effective, patient-centered hormonal healthcare. Mary also co-stars in PBS’ Healthy Hormones TV series. Mary also serves on HealthCentral’s Health Advocates Advisory Board.