Top Supplements to Consider During Pregnancy

Published on October 29, 2014 by Dr. Colin O'Brien

Proper nutrition is the foundation for any pregnancy. However, even pregnant women eating a well-balanced diet may need additional support for their body and their growing child. Here is a quick list of nutrients that should be considered for deficiency testing and/or supplementation to ensure a happy pregnancy and healthy baby.

Vitamin D3: Vitamin D is commonly deficient within the general population, therefore it only makes sense that expecting mothers’ fall into this same category. High intake of maternal Vitamin D3 during pregnancy has been inversely related to the development of asthma and allergic rhinitis in the offspring. This makes sense when we consider that Vitamin D is an integral part of the immune system and its development. The impact of vitamin D3 supplementation on offspring bone mineral content appears less clear, but may be worth considering in high risk populations.

Fish Oil: Fish oil contains both omega-3 fatty acids eicosapentanoic acid (EPA) and docosahexanoic acid (DHA), although DHA has proven to be most important during pregnancy. DHA supplementation has been found to improve the cognitive function of infants later in life. It has also been shown that taking fish oil during pregnancy increases birth weight and reduces the incidence of preterm births. Even though eating fatty fish (ie. salmon) does provide high levels of these omega-3 essential fatty acids, it is a problematic practice because heavy metal contamination may be present. In this circumstance, supplementation is preferred over dietary sources.

5-Methyltetrahydrofolate (a.k.a 5-MTHF or “active” folic acid): It’s well known that folic acid is imperative for proper development of the fetus and to prevent neural tube birth defects (such as spina bifida). This is largely why food production is now so heavily fortified with folic acid. However, if women are supplementing, it is crucial that the nutrient is in the form of 5-MTHF. 5-MTHF is considered an “active” form of folic acid that the body can utilize immediately. When synthetic folic acid is ingested, conversion and activation must occur in order to obtain 5-MTHF and utilize it within the body. The problem is that a large percentage of the population cannot effectively carry out this process (up to 50% of the population has an impaired ability to convert folate to 5-MTHF!), so direct 5-MTHF supplementation is recommended.

Iron: Iron deficient anemia is a very common concern during pregnancy. For this reason, it is important that supplementation begins as early as possible, especially in those women prone to low iron levels. For women that find iron supplementation to be very constipating, it is worth trying various forms of iron such as ferric pyrophosphate, ferric bisglycinate or ferrous succinate. Otherwise, a viable and safe alternative is lactoferrin. Lactoferrin is a protein that has been studied in pregnant women and shown to safely and effectively increase iron levels without the need for supplemental iron.

Probiotics: Healthy bacteria are not only important for the health of our digestive tracts, there is research to suggest that taking probiotics during pregnancy may reduce atopic dermatitis (i.e. eczema) in infants. It is commonly recommended to begin probiotic supplementation during pregnancy and continue until breastfeeding is complete to receive the most benefit for your newborn child.

Magnesium: Given that magnesium is the most deficient mineral in the North American diet, this deficit is only aggravated by pregnancy. Magnesium is necessary to help regulate blood pressure and may be indicated to help prevent a condition during pregnancy called pre-eclampsia (a main feature of which is high blood pressure). A deficiency of magnesium may also aggravate muscle cramping, a common concern in pregnancy.

As always, it is best for a qualified caregiver to handle any type of over-the-counter medication, health supplement or pharmaceutical drug during pregnancy in order to best suit your personal health circumstances. A qualified practitioner will help you safely decide what type of lab testing is necessary, which supplements should be considered, and at what dosages are optimal.

Image by © 2014 rocketclips via DollarPhotoClub


Erkkola M, Kaila MN, et al. Maternal vitamin D intake during pregnancy is inversely associated with asthma and allergic rhinitis in 5-year-old children. Clin Exp Allergy. 2009; 39(6):875-82.

Lawlor AD et al. Association of maternal vitamin D status during pregnancy with bone-mineral content in offspring: a prospective cohort study. The Lancet 2013; 381(22): 2176 – 2183

Salvig JD, Lamont RF. Evidence regarding an effect of marine n-3 fatty acids on preterm birth: a systematic review and meta-analysis. Acta obstetricia et gynecologica Scandinavica 2011; 90(8): 825-38

Dunstan JA, Simmer K, Dixon G, Prescott SL. Cognitive assessment of children at age 2(1/2) years after maternal fish oil supplementation in pregnancy: a randomised controlled trial. Arch Dis Child Fetal Neonatal Ed. 2008;93(1):F45-50.

Papakostas GI et al. L-methylfolate as adjunctive therapy for SSRI-resistant major depression: results of two randomized, double-blind, parallel-sequential trials. Am J Psychiatry. 2012;169(12):1267-74.

Paesano R, Pacifici E et al. Safety and efficacy of lactoferrin versus ferrous sulphate in curing iron deficiency and iron deficiency anaemia in hereditary thrombophilia pregnant women: an interventional study. Biometals 2014; 27(5): 999-1006

Doege K, Grajecki D, Zyriax BC, Detinka E et al. Impact of maternal supplementation with probiotics during pregnancy on atopic eczema in childhood – a meta-analysis. British J of Nut 2012; 107(1):1-6

Schoenaker D, Soedamah-Muthu SS and Mishra GD. The association between dietary factors and gestational hypertension and pre-eclampsia: a systematic review and meta-analysis of observational studies. BMC Med. 2014 Sep 22;12(1):157.