In a sample of 47 prenatal multivitamin and mineral supplements available on the market, less than half contained the recommended amount of essential nutrients choline and iodine, according to a study conducted by a team of researchers at University of Colorado Anschutz.
 
In the study, which was funded by the Center for Science in the Public Interest, researchers purchased 32 non-prescription and 15 prescription prenatal products, testing them for choline and iodine content (compared to what was listed on the label) as well as heavy metals like lead, arsenic, and cadmium. The supplements were tested via liquid chomatograph mass spectrometry and inductively coupled plasma mass spectrometry.
 
The authors of the study sourced their test products from Amazon using keywords “prenatal” and “prenatal vitamins,” as well as from chain pharmacies. Prescription products were identified through pharmacy online ordering platforms for “prenatal” and “prenatal vitamins” in four chain pharmacies.
 
The authors tested whether the supplements came within 20% of the claimed nutrient content, as well as whether they were within official safety standards. The Food and Nutrition Board of the Institute of Medicine recommends 450 mg of choline per day during pregnancy and 550 mg per day during lactation, with a tolerable upper limit of 3,500 mg per day. It’s recommended to take 150 mcg per day of iodine for adult women, which goes up to 220 mcg per day during pregnancy and 290 mcg per day during breastfeeding. The authors tested the heavy metal content of the supplements against United States Pharmacopoeia (USP) purity standards for pharmaceuticals.
 
Results
 
Only 12 of the prenatal supplements (26%) actually listed choline content, and only five of the tested products had the correct amount of choline compared to what was listed on label. Meanwhile, only 53% of products listed iodine content, and only four (16%) of the products tested contained the claimed amount of iodine. “Choline and iodine amounts are frequently omitted from their labels, despite both nutrients being essential for fetal growth and development,” the authors wrote.
 
Choline amounts were reported on 37.5% of non-prescription labels and none of the prescription labels. Of the 12 non-prescription products with choline reported on the label, the average of three samples was calculated to determine actual content. Based on the average amount, five were within 20% of the claimed amount, two were over the claimed amount by more than 20%, and 5 were under the claimed amount by more than 20%.
 
Iodine amounts were reported on 23 of 32 (71.9%) non-prescription product labels and 2 of 15 (13.3% of prescription product labels. Of the 23 non-prescription products with iodine reported, an average of three samples was calculated. Based on the averages, four were within 20% of the claimed amount, 19 were under the claimed amount by more than 20%, and none were in excess by over 20%. Of the two non-prescription products, both were under the claimed amount by more than 20%.
 
Five non-prescription and two prescription products had arsenic levels above the USP purity limit for pharmaceuticals. One prescription and one non-prescription product contained excessive lead. Amounts of cadmium above the USP limit were found in 13 non-prescription products and none of the prescription products.
 
 “Toxic exposures of heavy metals have been associated with infertility and miscarriage, obstetric outcomes such as preterm birth and low birth weight, neurodevelopmental delay such as autism and attention deficit hyperactivity disorder, and adult and childhood cancer,” the authors wrote.
 
“Current prenatal multivitamin and mineral labels are misleading with the potential to harm pregnant persons and fetuses through omission or inaccurate content of essential nutrients and inclusion of heavy metals,” the authors of the study concluded.
 
A similar study, conducted earlier this year by the Government Accountability Office, found that 11 of 12 supplements it tested contained at least one nutrient above or below acceptable deviations established by the U.S. Pharmacopoeia for folic acid, iodine, iron, or vitamin A, C, or E.