Less than half of prenatal supplements provide adequate levels of choline and iodine

Many Prenatal Vitamins Fall Short on Key Nutrients and Contain Toxic Metals, Study Finds

A new study published in The American Journal of Clinical Nutrition reveals that many prenatal vitamins lack sufficient levels of essential nutrients for a healthy pregnancy, while others contain harmful levels of toxic metals.

The research focused on the amounts of two critical nutrients—choline and iodine—in both nonprescription and prescription prenatal vitamins, as well as testing for the presence of toxic metals like arsenic, lead, and cadmium.

“During pregnancy, many women depend on prenatal vitamins to support their health and their baby’s development. Choline and iodine are especially vital for fetal development. However, our study found that some products do not contain the claimed amounts—or even lack these nutrients entirely,” said lead author Laura Borgelt, PharmD, MBA, a professor at the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences at CU Anschutz. “This research aims to empower women with better information so they can make more informed choices for their health and their baby’s well-being.”

Key Findings

The researchers tested 47 prenatal vitamins (32 nonprescription and 15 prescription) purchased from online and local retailers, comparing their actual nutrient content against what was listed on their labels. They also assessed the levels of toxic metals present.

Choline

• Only 12 products (26%) listed choline on the label.
• Of these, just five (42%) contained the correct amount as claimed.
• Choline, recommended at 450 mg/day during pregnancy, was often missing or inaccurately measured.

Iodine

• 53% of the products listed iodine on the label, but only four (16%) contained the advertised amount.
• Iodine is crucial during pregnancy, with a recommended intake of 220 mcg/day.

Toxic Metals

• Seven products exceeded safe levels for arsenic.
• Two products had dangerously high levels of lead.
• Thirteen products contained cadmium above purity limits.
• Exposure to these heavy metals during pregnancy is linked to adverse birth outcomes.

Safety Standards

The Food and Nutrition Board recommends a dietary intake of 450 mg/day of choline and 220 mcg/day of iodine during pregnancy. The U.S. Pharmacopeia also sets strict purity standards for harmful metals, including arsenic (2.5 mcg), lead (0.5 mcg), and cadmium (0.5 mcg) per daily dose.

A Call for Stronger Oversight

“Our study uncovered significant discrepancies between what’s listed on labels and what’s actually in these products,” Borgelt explained. “The presence of contaminants like cadmium is particularly concerning and underscores the urgent need for stronger regulatory oversight of prenatal supplements.”

Despite these findings, the researchers emphasize that prenatal vitamins remain an important part of pregnancy health. They recommend that women carefully review ingredient labels and consult healthcare professionals to choose the best supplements.

Next Steps

This research, funded by the Center for Science in the Public Interest through a grant from the John Sperling Foundation, highlights the need for more stringent monitoring of supplement quality and accuracy. It also underscores the importance of informed decision-making when selecting prenatal vitamins to ensure both mother and baby receive the nutrients they need without unnecessary risks.