Prescription prenatal vitamins may have lower doses of key ingredients like vitamin A, vitamin D, and calcium than nonprescription alternatives, a recent study suggests. Even though prenatal vitamins are widely recommended to pregnant women to help meet the nutrient needs for mothers and babies, women may struggle to choose the right supplement because labeling is inconsistent and the amount of the active ingredients varies widely from one product to the next, researchers note in the Journal of the Academy of Nutrition and Dietetics.
There’s no single right choice, experts say. Pregnant women should discuss their diet with their doctor before choosing a supplement, and try as much as possible to get needed nutrients from the foods they eat during pregnancy, said Deborah O’Connor, a nutrition researcher at the University of Toronto who wasn’t involved in the new research.
For the study, investigators examined labeling for 82 prescription and 132 nonprescription products in the U.S. They looked for doses of seven vitamins and minerals, non-nutrient ingredients, and safety information. Overall, prescription products had higher amounts of folic acid, which helps prevent brain and spinal cord birth defects, the study found. Prescription supplements typically had fewer vitamins – 9 compared with 11 for nonprescription options – and fewer minerals – 4 compared with 8 for nonprescription products.
“They can vary substantially in their nutrient content,” said lead study author Dr. Leila Saldanha, of the Office of Dietary Supplements at the National Institutes of Health. “Generally, most provide the amounts of nutrients that are recommended during pregnancy,” Saldanha said by email. “Overall, however, prescription prenatals are less potent than nonprescription prenatals, except for folic acid.”
Both types of supplements had similar amounts of zinc, iron and docosahexaenoic acid (DHA), an omega-3 fatty acid in fish oil that can support healthy development of a baby’s brain, nervous system and eyes, the study also found. All of the vitamins had higher than the recommended dose of at least one nutrient, based on U.S. dietary guidelines for pregnant and lactating women.
About 33 percent of the nonprescription products contained botanical ingredients, compared with 6 percent of prescription prenatals. Nonprescription products were also more likely to contain probiotics, although only 8 percent did, compared with 2 percent of prescription alternatives. Only prescription products contained the stool softener docusate sodium.
