How Many Prenatal Vitamins Contain Iodine: 2026 Report

Prenatal Vitamin Brands and Iodine

In the table below, we list the 12 brands with the most prenatal multivitamins on the market and show how many of each brand's products list iodine.

Our team took three findings from the brand data:

• We found that 108 of the 184 brands list iodine on every prenatal they sell, while 47 list it on none.
• Our data showed that the brands with the lowest iodine rates are prescription makers: Vertical Pharmaceuticals lists iodine on 1 of 8 products and Trigen Laboratories on 3 of 11.
• We found that large over-the-counter brands such as GNC Women's and Bayer One A Day list iodine on every prenatal in their range.

Daily Iodine Amount Compared With the Recommended Dose

In the table below, we group every prenatal multivitamin by the daily iodine it lists and split each group into prescription and over-the-counter products. The 150 mcg and 220 mcg marks match the American Thyroid Association's supplement advice and the pregnancy allowance.

Our researchers drew three conclusions from the dose data:

• We found that 45 products list between 220 and 290 mcg, enough to cover the full pregnancy allowance from the supplement alone, and 43 of them are sold over the counter.
• Our data showed that 19 products list some iodine but less than 150 mcg, so a label that mentions iodine can still fall short of the recommended dose.
• We found that prescription prenatals cluster at two points: 63 list no iodine and 40 list exactly 150 mcg, with only 8 anywhere else.

Iodine in Prescription vs Over-the-Counter Prenatal Vitamins

In the table below, we compare prescription prenatals, which reach patients through a clinician, with prenatals sold over the counter. The kelp column shows the share of iodine-listing products in each group that use kelp as the source.

Our team took three findings from the prescription data:

• We found that prescription prenatals are 29.9 percentage points less likely than over-the-counter prenatals to list iodine.
• Our data showed that only 3.6% of prescription prenatals list 220 mcg or more, against 21.5% of over-the-counter products.
• We found that no prescription prenatal relies on kelp, and 97.9% of those that list iodine use potassium iodide or iodate, the form the American Thyroid Association specifies.

Iodine in Prenatal Vitamins by Product Form

In the table below, we break down iodine by the form each prenatal comes in, using the physical form recorded in the NIH database. The median column shows the typical daily amount among products in each form that list iodine.

Our researchers drew three conclusions from the form data:

• We found that capsules are the form most likely to list iodine, while tablets, the most common form with 170 products, list it least often among single-pill forms.
• Our data showed that gummies list iodine 70.0% of the time and have the highest median dose of any single-pill form, 160 mcg.
• We found that kelp appears mostly in tablets, where it is the iodine source on 22.0% of iodine-listing products, compared with 2.1% of softgels.

Iodine in Prenatal Vitamins by Year Added to the Database

In the table below, we group products by the year their most recent label version entered the database, which shows how the formulas on file have shifted over time. The last column shows the share of iodine-listing products in each period that use potassium iodide or iodate.

Our team took three findings from the timeline data:

• We found that labels entered from 2023 to 2025 list iodine 28.6 percentage points more often than labels entered from 2020 to 2022.
• Our data showed that 30.0% of the newest labels list 220 mcg or more, more than six times the 4.8% among labels from 2012 to 2015.
• We found that the 2020 to 2022 period, the largest group at 140 products, lists iodine at nearly the same rate as 2012 to 2015, 53.6% against 53.2%.

Iodine Sources in Prenatal Vitamins

In the table below, we break down the iodine source listed in the supplement facts of every product that lists iodine, show how often each source reaches 150 mcg, and compare the mix with the best-selling prenatals of 2016 to 2017.

Our researchers drew three conclusions from the source data:

• We found that potassium iodide's share has held near three quarters since 2016 to 2017, while kelp's share fell by about two-fifths.
• Our data showed that kelp-based prenatals are the least likely to reach 150 mcg, at 80.6%, compared with 93.3% of products using potassium iodide or iodate.
• We found that the source is a practical check for shoppers: the NIH notes the body absorbs almost all potassium iodide, 96.4%, and the 2019 study's authors flagged non-iodide sources as highly variable.

How Prenatal Vitamin Iodine Has Changed Since 2009

In the table below, we compare our count with the two earlier published counts of iodine in US prenatal vitamins. Each study used a different set of products, so we show the scope of every count alongside its result.

Our researchers drew three conclusions from the comparison:

• We found that the share of prenatals with iodine on the label rose 12.7 percentage points from 2009 to 2026.
• Our data showed that best-selling prenatals were already ahead in 2016 to 2017, when 76.8% of doses sold contained iodine, which means the biggest sellers were more likely to include it.
• We found that the 2009 study also measured the iodine in each pill and found it varied by plus or minus 50% from the label, so label counts like ours show what is promised, not what is delivered.

What the Iodine Counts Mean for Prenatal Shoppers

For anyone planning a pregnancy, the practical result is that the word prenatal does not settle the iodine question. Over-the-counter products and newer labels carry iodine more often, prescription products less often, and the source and dose vary from brand to brand, so the supplement facts panel is the only reliable check.

Across 17 years of published counts, the share of prenatals with iodine has moved up, and the sources have shifted toward potassium iodide. The gap that remains is concentrated in prescription products and older labels.

So if you are comparing prenatals, look for 150 mcg of iodine as potassium iodide on the supplement facts panel before you buy.