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Prenatal Vitamins 101

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How to choose prenatal vitamins

Choosing prenatal vitamins can be difficult with the vast array of brands available. While it has long been recognized that folic acid is important during the prenatal period, all vitamins and minerals are required for healthy fetal development. A good quality prenatal vitamin is like an insurance policy – ensures you are getting all the necessary nutrients each day to avoid issues.

Here are some things to consider when choosing a prenatal vitamin. For the purpose of this article, I’ve compared a popular over-the-counter (OTC) prenatal vitamin (Materna), a prescription (Rx) prenatal commonly prescribed by MD’s (Preg-Vit), and two professional line (PL) prenatal vitamins (NFH Prenatal SAP and BioClinic Naturals PreFoundation).


The amount of nutrients in prenatal vitamins varies widely. While most brands now contain the recommended 1 mg of folic acid, there are still a few out there containing only 400-600 micrograms (mcg) per daily dose; a prescription version exists containing 5 milligrams (mg). Other B vitamin dosages vary even more. For example, in a daily dosage of the OTC or Rx prenatal, there is 2.6 mcg and 12 mcg of vitamin B12, while in both PL prenatals there is 1000 mcg. Vitamin B12 is important for DNA replication and neurological development in the baby and reduces pregnancy complications. Vitamin D levels are also important to watch – while both PL vitamins contain the recommended minimum 1000 IU, the OTC only contains 400 IU, and Rx comes in third with 250 IU per daily dose.


The form of nutrients found in prenatals affects the body’s ability to absorb them efficiently. For example, the active form of folic acid (called L-5-methyltetrahydrofolate, or MTHF) is the form the body requires. Folate, or folic acid, must be converted into MTHF in the body before it can be used. Up to 65% of women lack the genes necessary to effectively convert folic acid into MTHF, and can therefore not metabolize regular folic acid properly. Using a prenatal which contains MTFH instead of folic acid is an easy way to avoid this issue. OTC and Rx vitamins both contain folic acid, while both PL brands contain MTHF (all 1 mg).

Vitamin B12 forms also vary, with OTC and Rx vitamins containing inactive cyanocobalamin, the PL versions both carry the activated methylated form of B12.

Iron provides yet another good example. OTC and Rx prenatals both contain ferrous fumerate, which commonly causes gastrointestinal (GI) side effects like nausea and constipation. Both PL brands contain iron glycinate or bisglycinate, which tend to have fewer GI side effects.


This is can be a shocking discovery when you take a closer at the labels! Some prenatals contain unnecessary ingredients, common allergens and colourings which can cause reactions in some women. For example, the OTC vitamin contains red food colouring, corn starch, mineral oil, sodium lauryl sulfate (a foaming agent), soybean oil and gelatine to name a few. The Rx vitamin contains several dyes (blue, red and yellow), macrogol (a laxative), sodium lauryl sulfate, cornstarch and a shellac glaze (like nail polish, which is made from insect resin). Professional line products typically aren’t free of fillers, but they tend to be minimal. The ones used for comparison were contained in a vegetable capsule and included vegetable magnesium stearate, microcrystalline cellulose and silicon dioxide.

Price is also a consideration when choosing prenatal vitamins. While OTC brands tend to be less than $10 for a monthly supply, PL brands can be a bit more at $20 to $30 per month’s supply. Rx brands are pricey if you don’t have a drug plan ($38 for Preg-Vit, and $50 for Preg-vit 5), but if you have drug coverage you’ll just pay the pharmacy dispensing fee.

Happy Choosing!

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