A woman may wonder why her doctor prescribed a prenatal supplement when the prenatal multivitamins she saw at the health food store were more potent. It might simply be convenience considering most over-the-counter (OTC) prenatal vitamins have benefits beyond their prescription counterparts. Compared with prescription, most OTC prenatals have three to four times the amount of many vitamins and minerals while staying within safe dosage limits. Achieving these higher micronutrient intakes, however, often requires one to two capsules up to three times a day. Prescription multivitamins are usually taken once a day.

An informal comparison of four OTC prenatal supplements available at health food stores and nine prescription supplements listed in the Physician's Desk Reference reveals that the OTC supplements, though considerably higher in almost all the micronutrient levels, were usually lower in iron and folic acid. The amounts of both nutrients were adequate, however, averaging 36 mg and 800 mg, respectively. Women should take the dose recommended on the label, or follow the recommendation of a health care practitioner.

OTC supplements offer the advantage of being easily digested gelatin capsules vs. the hard tablets typical of prescription multivitamins. Sari Gallegos, N.D., a licensed midwife in Seattle, Wash., notes that gastrointestinal function can be less than optimal during pregnancy; "The prenatal supplements I recommend for my clients contain digestive enzymes because absorption is often more difficult during pregnancy."

In addition to digestive enzymes, some OTC multivitamins include medicinal herbs, which, in the case of ginger, may also improve digestibility. Unfortunately, sometimes there isn't enough herb present for a beneficial effect.

Finally, ingredient quality of some of the prescription prenatal supplements may compromise their usefulness. Most of the prescription prenatals reviewed contained calcium carbonate and ferrous fumarate, which, while less expensive, are not as well absorbed. Supplements available at health food stores may contain the more easily absorbed calcium citrate malate and iron/amino acid chelates.¹

—CKR

References

1. Smith KT.
Calcium absorption from a new calcium delivery system.
Calcif Tissue Int 1987;41:351-2