Prenatal vitamins can help bolster health during pregnancy, but being careful about which ones to take is important. For example, new research indicates that some may even be dangerous.
“Many prenatal vitamins don’t contain enough of the nutrients that are essential for a healthy pregnancy, while others contain harmful levels of toxic metals,” said a Thursday press release from the University of Colorado Anschutz Medical Campus.
A study authored by researchers from the university was published this week in The American Journal of Clinical Nutrition. It included a sample of 47 different prenatal vitamin, including 32 non-prescription and 15 prescription products that the researchers checked for arsenic, lead and cadmium – toxic chemicals. They also checked the vitamins for choline and iodine, two nutrients that are essential ingredients for fetal development.
“Some prenatal vitamins may not contain the exact amounts listed on the label and some may not contain any choline or iodine,” said the study’s first author Laura Borgelt, professor at the University of Colorado Skaggs School of Pharmacy and Pharmaceutical Sciences at CU Anschutz. “Our study aims to help women better understand the nutrient content in prenatal supplements, empowering them to make more informed choices and select the best options for their health and their baby’s well-being.”
For reference, 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. Recommended iodine intake is 150 mcg per day for women age 19 and older, increasing to 220 mcg per day during pregnancy and 290 mcg per day during lactation.
“The researchers found most prenatal vitamins do not list choline, and many of those that do, don’t contain the correct amount,” said the University of Colorado Anschutz Medical Campus. “Only 12 listed the choline content, which is about 26% and only five products (42%) had the right amount of choline as promised on the label.”
As for chemicals to avoid, the United States Pharmacopeia established purity standards with limits for arsenic of 2.5 mcg per oral daily dose of arsenic, 0.5 mcg per oral daily dose of cadmium and 0.5 mcg per oral daily dose of lead.
Out of the 47 products tested for the study, seven products had too much arsenic, two had too much lead and 13 had too much cadmium.
Exposure to these heavy metals is linked to adverse pregnancy outcomes. Per the U.S. Centers for Disease Control and Prevention, heavy metal exposure is associated with miscarriage, stillbirth and birth defects as well as brain development complications if heavy metals enter breast milk.
“The presence of contaminants, especially cadmium, was also concerning,” Borgelt said. “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.”
In the meantime, the researchers recommend double-checking ingredients and working with healthcare professionals to find the safest prenatal supplements. According to the American Pregnancy Association, “there is no such thing as a ‘perfect’ prenatal vitamin,” that can meet all prenatal needs, and supplements should be paired with a healthy diet and exercise routine.