Kelly Wright
CNC (Certified Nutrition Consultant - pregnancy, postpartum & baby nutrition), Certified Holistic Nutrition Coach
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Pregnancy places extraordinary demands on the body, and even with the best intentions, many women find it challenging to meet all their nutrient needs through diet and supplements alone.
While prenatal vitamins are often recommended as a safety net, research shows that gaps can remain. These shortfalls may affect
- maternal wellbeing
- pregnancy outcomes
- baby’s long-term health
The first part of this series looks at four of the most common deficiencies worldwide:
- Iron
- Vitamin D
- Choline
- Vitamin B9 (Folate)
exploring why they matter, how deficiencies can show up, and why a food-first approach is often the most effective foundation for support.
Iron
Iron is one of the most critical nutrients in pregnancy. It’s needed to support the rapid growth of the baby and the expansion of the maternal blood volume. Globally, iron deficiency, or iron deficiency anemia, complicates nearly half of all pregnancies.[1] Deficiency can lead to :
- maternal anaemia
- debilitating fatigue
- low quality of life
- restless legs
- poor immune function
- increased risks of preterm birth
- cesarean delivery
- postpartum hemorrhage (in rare cases, maternal death)
- low birth weight
- preterm birth[2]
For babies, there is a risk of potential long-term impacts on brain development, memory, and early bonding.
Iron is one of the most critical nutrients in pregnancy
Although iron is included in most prenatal supplements, it’s not always effectively absorbed. This is because many competing factors influence iron absorption.
Because the body prioritises iron for essential functions during pregnancy, even small shortfalls can quickly deplete stores, making it important to focus on both meeting daily needs and creating the right conditions for absorption.[1]
Nutrients like calcium and zinc, when taken simultaneously, can compete for uptake in the gut, while compounds such as phytates (found in grains and legumes) can further inhibit their absorption.[2]
RELATED — Zinc (for immunity, skin health and libido)
On the other hand, vitamin C-rich foods can enhance the absorption of non-heme iron (plant-based forms).[2]
RELATED — Vitamin C (Immunity and Collagen booster)
The body tightly regulates iron absorption through the gut and has no active way to eliminate excess iron, so it carefully controls how much is absorbed.
From a typical intake of 10–15mg per day, only 1–2mg is usually absorbed, depending on the form of iron and what it’s consumed with.[2] This is why relying solely on a supplement may not always restore optimal iron status, especially if absorption is compromised.
RELATED — Iron (for immunity support and energy production)
Choosing iron-rich whole foods, such as
- red meat
- liver
- slow-cooked meats
alongside meals that support absorption, can make a meaningful difference.[2]
While iron deficiency is one of the most well-known concerns in pregnancy, another nutrient that consistently falls short is vitamin D. Its role goes beyond bone strength and has far-reaching effects on immune function, pregnancy complications, and even long-term child outcomes.
Vitamin D
Vitamin D deficiency is now recognised as a global and widespread issue impacting human health, and growing evidence has linked it to:
- bone health problems
- impaired immune function
- increased risk of gestational diabetes during pregnancy[3]
Research also connects low maternal vitamin D status with a higher risk of other complications, such as:
- pre-eclampsia
- preterm birth
- delivering a low birth weight infant[4]
Vitamin D can be synthesised in the skin through exposure to UVB sunlight or obtained through diet and supplementation.[3,5]
Dietary sources include animal-based foods like:
- Fatty fish
- Fish liver oils
- Beef liver
- Cheese
- Eggs
RELATED — Everything You Need to Know When Buying Eggs (Part 1)
Fortified foods such as milk, yoghurt, breakfast cereals, orange juice, and plant-based beverages also contribute to intake; however, these forms are often poorly absorbed.
Vitamin D is primarily found in two forms:
- D3 (cholecalciferol), the more effective form, is found in animal products[5]
- D2 (ergocalciferol) is typically found in fortified or plant-based sources[5]
Because vitamin D is fat-soluble, it absorbs best when consumed with dietary fat or in an oil-based supplement.[3] Some animal-derived foods also contain 25-hydroxy vitamin D, a metabolite supporting vitamin D status.
However, few foods naturally provide more than 160 IU per 100g, making it difficult to meet the recommended 4000 IU/day through diet alone.[5]
RELATED — Vitamin D: The sunshine hormone for stronger bones
During pregnancy, the demand for vitamin D increases due to its role in placental function and calcium metabolism, both of which are essential for fetal bone development.
RELATED — Calcium (for healthy bones, teeth and heart)
The MDPI review emphasises that adequate vitamin D helps regulate genes involved in implantation and placental development, which may influence pregnancy outcomes.[4]
During pregnancy the demand for vitamin D increases
While supplementation is often recommended when a deficiency is identified, it is not a one-size-fits-all solution.
Deficiency may persist despite low-dose supplementation, particularly in those with limited sun exposure or absorption challenges.[3]
Rather than relying solely on supplements, a whole-food, nutrient-rich diet combined with safe sun exposure offers a more balanced and supportive approach to maintaining vitamin D levels and overall maternal health.
Unlike vitamin D, which has gained more recognition in recent years, choline has remained largely overlooked in prenatal care. Yet its role in brain development, placental function, and even stress resilience makes it a nutrient deserving much greater attention.
Choline
Choline is a vital nutrient during pregnancy, yet most women aren’t getting enough. Around 90–95% of pregnant women fall short of the recommended intake, and most prenatal vitamins don’t contain adequate amounts, or any at all.[6,7]
Choline plays a critical role in fetal brain development, particularly in forming the hippocampus, the area responsible for learning and memory.[7] It also supports:
- placental function
- helps build the structure of cell membranes
and is involved in:
- neurotransmitter production
- nutrient transport
- DNA regulation
making it essential for maternal and infant health.[7]
Choline plays a critical role in fetal brain development
According to emerging research, choline’s role extends into epigenetic regulation, influencing how genes involved in brain development, metabolism, and stress response are expressed in the fetus.[8]
This may partly explain why higher maternal intakes have been linked to improved cognitive processing speed and memory in children.[8]
Because the body can’t produce enough choline on its own, dietary intake becomes essential. During pregnancy, the demand rises significantly to support the rapid growth of the baby’s brain and organs.[7]
Rich sources include egg yolks, liver, and beef, which are often underconsumed in modern diets.[9]
Research shows that low choline levels are linked to neural tube defects, similar to folate deficiency, as well as an increased risk of preeclampsia, preterm birth, and poor infant neurodevelopmental outcomes.[9]
There is also evidence that adequate choline during late pregnancy may buffer the effects of prenatal stress on the child’s brain development, potentially reducing later vulnerability to mental health disorders.[8]
Even moderate improvements in maternal choline intake have been associated with enhanced cognitive outcomes in offspring. This suggests that food-based strategies to increase choline may offer long-term benefits for child development.[7]
Despite its importance, choline remains one of the most overlooked nutrients in pregnancy care.
A food-first approach, prioritising nutrient-dense wholefoods, can help bridge this gap more effectively than relying on standard prenatal supplements alone.
Choline and folate often work hand in hand in critical processes like one-carbon metabolism.
But while folate is widely recognised, often the first nutrient most people associate with pregnancy, its significance goes well beyond preventing neural tube defects.
Vitamin B9 (Folate)
Folate is one of the most essential nutrients in early pregnancy. It helps with
- DNA synthesis
- healthy cell growth
- baby’s brain and nervous system development[10]
It also supports gene expression and amino acid metabolism, vital throughout gestation.
Supplementing with folate before and during pregnancy is well known to reduce the risk of neural tube defects.[10] But its benefits go beyond this. Studies show folate may also reduce the risk of
- congenital disabilities
- preterm birth,
- and small-for-gestational-age babies
especially when taken in the lead-up to conception.[10]
RELATED — Vitamin B9 (Folate)
Yet folate needs increase significantly during pregnancy, and blood levels often drop without extra support.[10] Even with food fortification, many women still don’t meet optimal levels.
In one study, a supplement dose of 355mcg/day was enough to maintain healthy blood levels. Still, lower amounts were linked with higher rates of megaloblastic anemia caused by severe folate or B12 deficiency.[10]
A meta-analysis confirmed that folate supplementation reduced megaloblastic anemia risk by almost 80%.[10]
Research has also linked low folate with higher rates of preterm birth, small-for-gestational-age babies, and, in some cases, delayed language development in children.[10]
Folate appears to play a role in long-term neurological outcomes, and when it’s low, the risks can rise.
Wang et al. (2021) emphasise that folate sufficiency in the periconceptional period is one of the most effective strategies for preventing neural tube defects. They also note that maintaining adequate folate throughout pregnancy supports
- placental growth
- reduces certain hypertensive disorders
- may improve overall birth weight outcomes[11]
High levels of unmetabolised folic acid (from supplements and fortified foods) have been linked to increased autism and allergy risks.[10]
Approximately 60% of people have difficulty converting folic acid to its active form, making 5-MTHF (methylfolate) a more suitable option.
Beyond structural development, folate’s role in one-carbon metabolism underpins DNA synthesis and methylation, processes critical for rapid cell division and healthy fetal organ formation.[11]
Folate-rich foods include leafy greens, liver, legumes, and eggs
In Part 2 of this series, we’ll continue by exploring four more nutrients that are equally vital yet often under-recognised in pregnancy: vitamin B12, magnesium, DHA (omega-3 fatty acids), and iodine.
Kelly is a Certified Nutrition Consultant specialising in pregnancy, postpartum, and infant nutrition. With a strong foundation in both modern nutritional science and ancestral food wisdom, she supports women through the critical perinatal period with an emphasis on real food, bioavailable nutrients, and practical, evidence-based care…
If you would like to learn more about Kelly, see Expert: Kelly Wright.
References
(1) Benson, A.E., Shatzel, J.J., Ryan, K.S., Hedges, M.A., Martens, K., Aslan, J.E., Lo, J.O. The Incidence, Complications And Treatment of Iron Deficiency in Pregnancy. Eur J Haematol https://onlinelibrary.wiley.com/doi/full/10.1111/ejh.13870
(2) Piskin, E., Cianciosi, D., Gulec, S., Tomas, M., & Capanoglu, E. (2022). Iron Absorption: Factors, Limitations, And Improvement Methods. ACS Omega. https://pubs.acs.org/doi/10.1021/acsomega.2c01833
(3) Abdelmageed, R.M., Hussein, S.M.M., Anamangadan, S.M., et al. (2024). Prospective Cohort Study of Vitamin D Deficiency in Pregnancy: Prevalence And Limited Effectiveness of 1000 IU Vitamin D Supplementation. Women’s Health. https://journals.sagepub.com/doi/full/10.1177/17455057231222404
(4) Dovnik, A., & Mujezinović, F. The Association of Vitamin D Levels With Common Pregnancy Complications. Nutrients. https://www.mdpi.com/2072-6643/10/7/867
(5) Benedik, E. (2022). Sources of Vitamin D for Humans. https://econtent.hogrefe.com/doi/10.1024/0300-9831/a000733
(6) Mun, J.G., Legette, L.L., Ikonte, C.J., & Mitmesser, S.H. (2019). Choline and DHA in Maternal And Infant Nutrition: Synergistic Implications in Brain And Eye Health. Nutrients. https://www.mdpi.com/2072-6643/11/5/1125
(7) Derbyshire, E.J. (2025). Choline in Pregnancy And Lactation: Essential Knowledge for Clinical Practice. Nutrients. https://pmc.ncbi.nlm.nih.gov/articles/PMC12073457/
(8) Korsmo, H.W., Jiang, X., Caudill, M.A. Choline: Exploring The Growing Science on its Benefits for Moms And Babies. Nutrients.
(9) Roeren, M., Kordowski, A., Sina, C., & Smollich, M. (2022). Inadequate Choline Intake in Pregnant Women in Germany. Nutrients. https://www.mdpi.com/2072-6643/14/22/4862
(10) Adams JB, Kirby JK, Sorensen JC, Pollard EL, Audhya T. Evidence-based Recommendations for an Optimal Prenatal Supplement for Women in The US: Vitamins And Related Nutrients. Matern Health Neonatol Perinatol. https://mhnpjournal.biomedcentral.com/articles/10.1186/s40748-022-00139-9#citeas
(11) Wang, Y., Liu S., Pradhan, S., Zhong, Y., Ma, W., Xu T., Zhou, H., Zhang, X. Folic Acid Supplementation And Pregnancy Outcomes: A Systematic Review And Meta-Analysis. Frontiers https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2021.670289/full
