Research has revealed that a large proportion of prenatal vitamins don't contain enough of the essential nutrients associated with a healthy pregnancy.
This study, which can be found in the American Journal of Clinical Nutrition, revealed that many prescription and non-prescription prenatal supplements on the market don't contain sufficient levels of choline or iodine — crucial nutrients for pregnant individuals.
It also found that a notable proportion of the supplements tested contained toxic metals such as arsenic, lead and cadmium, which can be associated with adverse birth outcomes.
Assessing pain points in the prenatal vitamin market
To determine the safety and efficacy of the prenatal vitamin supplements available on the market, researchers from the University of Colorado's Anschutz Medical Campus assessed 47 different prenatal vitamins.
32 of these were readily available for purchase, while 15 of them required a prescription — with supplements purchased from online and local shops.
They then measured how much choline and iodine were present in the formulations, while also assessing the levels of toxic metals present in the chosen supplements.
“During pregnancy, many women rely on prenatal vitamins and minerals to support their health and their baby’s development. Among the most crucial nutrients for fetal development are choline and iodine." said the study's first author, Laura Borgelt, professor at the University of Colorado Skaggs School of Pharmacy.
Labelling discrepancies and lacking formulations
According to the Food and Nutrition offshoot of the Institute of Medicine, choline intake should stand at around 450mg per day during pregnancy, with this figure rising to 550mg per day during lactation — whereas iodine intake should be around 220 and 290 mcg per day in pregnant and lactating individuals, respectively.
Since the choline and iodine requirements rise significantly pre- and post-natally, its important for pregnancy-focused supplements to include these vital nutrients at a beneficial level.
When researchers at the University of Colorado quantified choline levels in the selected prenatal supplements, they found that most prenatal vitamins don't even list choline.
For those that do list choline as a core ingredient, a majority don't contain the amount promised on the label — with only five out of twelve products containing the advertised concentration of the nutrient.
Though iodine was listed as an ingredient in 53% of the tested supplements, only four contained the claimed amount of iodine that was depicted on the product's label.
Heavy metal contamination
Heavy metals can be harmful to consume, and this impact is exacerbated in pregnant individuals.
The United States Pharmacopeia states that consumers can safely ingest 2.5mcg per oral daily dose of arsenic, with figures for cadmium and lead standing at 0.5mcg per day.
Of the supplements assessed, seven contained too much arsenic, while two had more lead than desirable and 13 had too much cadmium.
These metals can be toxic when ingested, and have the potential to cause adverse health effects on both mother and baby.
“The presence of contaminants, especially cadmium, was also concerning. Our findings highlight a significant gap between what's listed on the labels and what’s actually in the products, underscoring the urgent need for stronger regulatory oversight in this area,” Borgelt added.
The results of this study highlight the need for supplement providers to ensure they are testing their formulations for active ingredients, while also managing contaminants.