5 Non-Negotiable Supplements During Pregnancy
As a dietitian, I am always preaching a food-first approach. But during pregnancy, our nutrient needs increase dramatically, making it challenging, and sometimes overwhelming, to meet every nutrient requirement through food alone.
When we add in the joys of morning sickness, nausea, food aversions, food fatigue, and vomiting, and even the best intentions can quickly go out the window. If you avoid certain foods or entire food groups due to personal preference, allergies, intolerances, or dietary choices, I highly recommend working with a Registered Dietitian to ensure you’re meeting your nutritional needs throughout pregnancy.
For example:
Excluding fish can significantly reduce iodine intake, which is important for thyroid function and your baby’s brain development.
Excluding eggs greatly reduces choline intake, a nutrient essential for neural tube and brain development.
Avoiding or limiting meat and dairy products can decrease iron, zinc, vitamin B12, calcium, and protein intake.
Every dietary pattern has its own nutritional considerations.
It’s also important to remember that the Recommended Dietary Allowance (RDA) was designed to prevent nutrient deficiencies—not necessarily to support optimal health or pregnancy outcomes. Just because a supplement provides100% of the RDA doesn’t automatically mean it provides the optimal amount for pregnancy.
So here are my five non-negotiable supplements during pregnancy to help fill common nutrient gaps—along with some food-first guidance.
1. A High-Quality Prenatal Vitamin
Think of your prenatal vitamin as your nutritional foundation. It helps cover many of the basics—but not all prenatal vitamins are created equal.
Many contain lower amounts of key nutrients or use forms that are not as easily absorbed by the body.
Look for a prenatal that contains:
Activated (methylated) B vitamins
600–800 mcg of folate, preferably as L-5-methyltetrahydrofolate (5-MTHF) rather than folic acid because these forms are readily usable by the body regardless of MTHFR genetic variations.
Vitamin D3 (if your prenatal doesn’t provide enough, supplement separately—see #4)
Vitamin K2
Zinc
Selenium
Iodine (unless your healthcare provider recommends otherwise)
Why it’s important:
A quality prenatal supports:
Neural tube development
Healthy fetal growth
Maternal nutrient stores
Prevention of common nutrient deficiencies
Think of it as nutritional insurance during a time when your nutrient needs are at their highest.
Tip: Take your prenatal with food to improve absorption and reduce nausea. It’s perfectly fine to split the dose between meals if that feels better on your stomach.
2. Choline
Recommended intake: 450–930 mg per day (from food and supplements)
While the current Adequate Intake (AI) is 450 mg/day, newer research suggests 930 mg/day may provide additional benefits for fetal brain development.
Why it’s important:
Choline supports:
Brain development
Neural tube development
Placental function
Healthy methylation
Long-term cognitive development
Higher choline intake has also been associated with a lower risk of:
Preeclampsia
Preterm birth
Small-for-gestational-age infants
Gestational diabetes
Unfortunately, only 6–10% of pregnant women meet the recommended intake.
Food sources:
Egg yolks (approximately 125–150 mg per egg)
Beef liver
Salmon
Beef
Chicken
Some high-quality prenatal vitamins contain choline, but rarely enough, so many women benefit from an additional choline supplement.
3. Omega-3 DHA
Recommended intake: 300–600 mg DHA daily at minimum
Many experts recommend around 1 gram of combined DHA and EPA daily, although individual needs vary. DHA is best paired with EPA (another kind of Omega-3 fat) for optimal absorption.
Why it’s important:
DHA supports:
Baby’s brain development
Eye development
Nervous system development
The third trimester is when your baby’s brain grows most rapidly, making adequate DHA especially important.
Food sources:
Excellent sources include:
Wild Alaskan sockeye salmon
Sardines
Anchovies
Herring
Mackerel
Fish roe (fish eggs)
Just 3 ounces of wild salmon or sardines can provide over 1,000 mg of DHA, making it very possible to meet your needs through food if you consume 2–3 servings of fatty fish each week.
If you don’t regularly eat cold-water fatty fish, consider a high-quality DHA/EPA supplement that has been third-party tested for heavy metals and contaminants.
For those following a vegetarian or vegan diet, algae oil is the only reliable plant-based source of DHA.
Tip: Take omega-3 supplements with a meal containing healthy fat to maximize absorption.
4. Vitamin D
Recommended intake: 4,000 IU daily (unless your healthcare provider recommends otherwise based on blood work)
Why it’s important:
Adequate vitamin D status has been associated with a lower risk of:
Preeclampsia
Preterm birth
Gestational diabetes
Low birth weight
Vitamin D is also essential for:
Calcium absorption
Bone health
Immune function
Healthy placental development
I encourage women to have their 25-hydroxyvitamin D level checked before or early in pregnancy whenever possible so supplementation can be individualized.
Why supplementation is often necessary:
Sunlight—not food—is our primary source of vitamin D.
However, many of us:
Spend most of our time indoors
Wear sunscreen
Cover our skin
Live in northern climates with limited UV exposure
As a result, supplementation is often necessary.
Since vitamin D is fat-soluble, it’s possible to take too much. That’s why testing is the best way to determine the appropriate dose.
Tip: Take vitamin D with a meal containing healthy fat to improve absorption.
5. Magnesium
Magnesium is involved in over 300 enzymatic reactions in the body and is one of the most common nutrient shortfalls during pregnancy.
According to the NIH, 53.3% of pregnant women in the United States consume less magnesium than the Estimated Average Requirement (EAR). Even after accounting for supplements, nearly half (47.5%) still fall below the EAR.
Recommended dose: Work up to 300 mg daily, if needed, under the guidance of your healthcare provider.
Which form?
I most commonly recommend:
Magnesium glycinate for general pregnancy support because it’s highly absorbable and gentle on the digestive system.
Magnesium citrate if constipation is a concern, since it has a mild laxative effect.
Why it’s important:
Adequate magnesium supports:
Healthy blood sugar regulation
Healthy blood pressure
Muscle function
Sleep quality
Reduced muscle cramps
Overall fetal growth and development
Food sources:
Pumpkin seeds
Chia seeds
Almonds
Cashews
Brazil nuts
Sesame seeds
Sunflower seeds
Dark leafy greens
Avocados
Dark chocolate
Beans and legumes
Don’t Forget the Food
Supplements fill nutritional gaps—they don’t replace food. Some of the most nutrient-dense pregnancy foods include:
Eggs
Salmon and sardines
Grass-fed beef
Full-fat dairy
Liver and other organ meats
Colorful vegetables
Fruit
Beans and lentils
Nuts and seeds
Whole foods provide thousands of beneficial compounds and in combinations that supplements simply can’t replicate. Supplements should be viewed exactly as their name suggests: supplemental to a healthy, nutrient-dense diet—not a replacement for one. I often compare it to this: Just because you take a greens powder doesn’t mean you can skip eating spinach or kale. Taking a vitamin C supplement doesn’t replace eating citrus fruits or bell peppers. Whole foods contain fiber, phytonutrients, antioxidants, enzymes, and countless other compounds that work together in ways supplements simply cannot replicate. Focus on building your plate first. Then use supplements to fill in the nutritional gaps.
Cheers to a healthy, comfortable and safe pregnancy and beyond.
About the Author
Erin McIntyre, Registered Dietitian | Functional Nutrition | Fertility & Women’s Health
Erin specializes in functional nutrition, fertility, hormone health, and women’s wellness. She combines evidence-based nutrition with a root-cause approach to help patients optimize their health through personalized nutrition, lifestyle medicine, and comprehensive metabolic assessment.
Inspired by her own experience navigating hormonal and reproductive health challenges, Erin is passionate about helping patients move beyond symptom management to better understand the underlying factors influencing their health. Her clinical approach integrates nutrition science, functional medicine principles, and behavior change to create practical, sustainable treatment plans tailored to each individual’s goals.
References
Aghajafari, F., Nagulesapillai, T., Ronksley, P. E., Tough, S. C., O’Beirne, M., & Rabi, D. M. (2013). Association between maternal serum 25-hydroxyvitamin D level and pregnancy and neonatal outcomes: Systematic review and meta-analysis of observational studies. BMJ, 346, f1169. https://doi.org/10.1136/bmj.f1169
Greenberg, J. A., Bell, S. J., & Ausdal, W. V. (2008). Omega-3 fatty acid supplementation during pregnancy. Reviews in Obstetrics & Gynecology, 1(4), 162–169.
National Institutes of Health, Office of Dietary Supplements. (n.d.). Pregnancy and lactation—Health professional fact sheet. U.S. Department of Health and Human Services. https://ods.od.nih.gov/factsheets/Pregnancy-HealthProfessional/
Nichols, L. (2018). Real food for pregnancy: The science and wisdom of optimal prenatal nutrition. Lily Nichols RDN.
Wallace, T. C., Blusztajn, J. K., Caudill, M. A., Klatt, K. C., Natker, E., Zeisel, S. H., & Zelman, K. M. (2018). Choline: The underconsumed and underappreciated essential nutrient. Nutrition Today, 53(6), 240–253. https://doi.org/10.1097/NT.0000000000000302
Wei, S. Q., Qi, H. P., Luo, Z. C., & Fraser, W. D. (2013). Maternal vitamin D status and adverse pregnancy outcomes: A systematic review and meta-analysis. Journal of Maternal-Fetal & Neonatal Medicine, 26(9), 889–899. https://doi.org/10.3109/14767058.2013.765849
