Pregnancy Supplements: What You Actually Need and When
By Kylie Sartori | Kylie Sartori Naturopathy, Spotswood Melbourne
Pregnancy is one of the most nutritionally demanding periods of a woman's life.
Your body is building an entire human being from scratch. Every organ, every cell, every system your baby will ever have is being formed in those nine months, and the raw materials come almost entirely from what you eat and absorb.
The question most pregnant women ask me is whether they are getting enough. And the honest answer is that even with a genuinely good diet, the nutritional demands of pregnancy are high enough that targeted supplementation almost always makes sense.
The challenge is knowing what you actually need, because the supplement aisle during pregnancy can feel completely overwhelming.
Here is how I think about it, and what I recommend to my clients.
Start Before You Are Pregnant
If there is one thing worth knowing about pregnancy nutrition, it is this.
The most critical window for certain nutrients, particularly folate, is the first four weeks of pregnancy. That is often before most women even know they are pregnant.
This is why I recommend starting a preconception multivitamin at least three months before you plan to conceive. Those three months allow your body to build adequate nutrient stores, support egg quality, regulate your cycle, and prepare your gut microbiome, all of which directly influence your ability to conceive and carry a healthy pregnancy.
If you are already pregnant and have not started yet, start now. It is never too late to support what is happening.
You can read more about preconception care and what a naturopathic approach to fertility looks like on my conditions treated page.
Why a Practitioner-Grade Prenatal Multivitamin Matters
Not all prenatal supplements are created equal, and this matters more than most people realise.
The form of each nutrient is just as important as the dose. Folic acid, the synthetic form of folate found in most supermarket prenatal vitamins, is not well converted by a significant proportion of women, particularly those with MTHFR gene variants. Methylfolate, the active form, is far more bioavailable and effective.
The same principle applies to B12, iron, magnesium, and zinc. The forms used in practitioner-grade supplements are chosen for absorption and tolerability, which is why clients who have been taking a supermarket prenatal and still testing deficient often see their levels improve quickly when they switch to a properly formulated product.
I use Naturobest prenatal multivitamins for my pregnant clients. They are formulated by a naturopath with the changing nutritional demands of each trimester in mind, which is an important detail because what your body needs in the first trimester is quite different from what it needs in the third.
As your pregnancy progresses, the demand for certain nutrients increases significantly, with the greatest requirements coming in the final trimester as your baby undergoes rapid brain development and lays down bone density. A quality prenatal multi that is designed to meet those changing demands removes a lot of the guesswork.
The Key Nutrients and Why Each One Matters
Folate
Folate is essential for healthy neural tube development and is the nutrient most consistently associated with reducing the risk of spinal cord defects, including spina bifida. The neural tube closes in the first 28 days of pregnancy, often before a positive test. This is why adequate folate before and immediately after conception is so critical. Beyond neural tube development, folate supports DNA synthesis, cell division, and healthy placental function throughout the entire pregnancy. Food sources include leafy greens, spinach, avocado, legumes, citrus, and beets. These are worth including abundantly throughout pregnancy alongside your prenatal supplement.
DHA
DHA is an omega-3 fatty acid and is arguably the most important single nutrient for your baby's developing brain and eyes. The brain undergoes its most rapid growth in the third trimester and the first two years of life, and DHA is the primary structural fat in brain tissue. Adequate DHA during pregnancy is associated with better cognitive development, visual acuity, and a reduced risk of preterm birth. Low omega-3 status has also been consistently linked to an increased risk of postnatal depression, which is worth knowing. Many prenatal multivitamins do not include adequate DHA, which is why a separate high-quality fish oil or algae-based DHA supplement is often worth adding. Food sources include salmon, mackerel, sardines, anchovies, walnuts, and flaxseeds.
Iron
Iron demand increases significantly during pregnancy because your blood volume expands by up to 50 per cent and your body is simultaneously building your baby's iron stores. Low iron is one of the most common nutritional issues in pregnancy and one of the most impactful. Iron deficiency anaemia in pregnancy is associated with significant maternal fatigue, impaired immune function, increased risk of preterm birth, and low birth weight. It also affects your baby's iron stores at birth, which matter for brain development in the first year of life. Many women find meat difficult to tolerate in the first trimester, which is exactly when nausea and food aversions are strongest. Supplementation during this window is particularly useful. Iron from food sources includes red meat, legumes, spinach, dried fruits, and fortified grains. Vitamin C taken alongside plant-based iron sources significantly improves absorption. Iron should ideally be tested and monitored throughout pregnancy rather than supplemented in the dark. Too much iron is as problematic as too little.
Magnesium
Magnesium is involved in over 300 enzymatic reactions in the body and is one of the most consistently depleted nutrients during pregnancy. It supports healthy nerve and muscle function, contributes to bone and teeth development in the baby, helps maintain healthy blood pressure, and is one of the most effective natural remedies for the leg cramps and muscle aches that many women experience in the second and third trimesters. It also supports sleep quality, which becomes increasingly elusive as the pregnancy progresses. Food sources include pumpkin seeds, chia seeds, leafy greens, brown rice, avocado, and dark chocolate. Most women still benefit from supplementation in pregnancy, even with a good diet, because the demand is high and stress and poor sleep deplete it further.
Calcium
Calcium demand increases significantly during pregnancy to support the development of your baby's bones and teeth. If dietary calcium is insufficient, your body will draw calcium from your own bones to meet the baby's needs, which has long-term implications for your bone density. Dairy products, dark leafy greens, almonds, tahini, chia seeds, tofu, and blackstrap molasses are the strongest food sources. Supplementation is worth considering if dairy is limited in your diet or if you have any concerns about your intake.
Vitamin D
Vitamin D supports immune function, bone development, and calcium absorption, and adequate levels in pregnancy are associated with a reduced risk of pre-eclampsia, gestational diabetes, and preterm birth. Deficiency is common in Australia despite our sunny climate, largely because most people spend the majority of their day indoors. Testing your vitamin D level at the start of pregnancy, or ideally during preconception, means you can supplement to reach an optimal rather than just sufficient level. Sun exposure, egg yolk, salmon, and tuna provide some dietary vitamin D, but supplementation is usually necessary to maintain adequate levels.
Vitamin K
Vitamin K is essential for blood clotting, healthy bone metabolism, and tissue repair. Getting adequate vitamin K during pregnancy helps prepare the body for labour and postpartum recovery. It also plays a role in ensuring newborns have adequate clotting capacity at birth, which is why vitamin K is routinely administered to newborns after delivery. Leafy green vegetables, fermented foods, and good-quality fats support vitamin K status during pregnancy.
Probiotics
This is one of the most important and underappreciated supplements in pregnancy. Your gut microbiome is directly passed to your baby during vaginal delivery. The microbial communities your baby acquires at birth and through breastfeeding form the foundation of their immune system, their gut health, and their long-term health trajectory. Research consistently shows that probiotic supplementation during pregnancy reduces the risk of Group B Streptococcus infection, gestational constipation, and yeast infections in the mother, and significantly reduces the incidence of colic, reflux, eczema, and allergies in the baby. Choosing the right strains matters. Lactobacillus rhamnosus GG and Bifidobacterium species are among the best studied for pregnancy. A practitioner-grade probiotic formulated specifically for pregnancy is the most appropriate choice, and continuing through breastfeeding extends the benefit to your baby.
A Note on Nausea and Supplement Tolerance
First trimester nausea can make taking supplements genuinely difficult. If swallowing capsules is triggering nausea, try taking your prenatal with a small amount of food rather than on an empty stomach, splitting doses across the day rather than taking everything at once, or temporarily switching to a liquid or powder form until nausea settles. Iron is often the most problematic for nausea and constipation. If standard iron supplements are not well tolerated, a gentle, food-based iron form like ferrous bisglycinate is usually much better tolerated and still well absorbed. If you are struggling significantly with nausea and it is affecting your ability to eat and supplement adequately, this is absolutely worth discussing in a consultation rather than pushing through alone.
Working Together
Every pregnancy is different, and your nutritional needs depend on your individual history, your diet, your gut health, and any test results from your current or previous pregnancies. A naturopathic consultation gives you a clear and personalised picture of what your body specifically needs through each trimester, so you are not supplementing in the dark or paying for nutrients you do not need. I see clients in person at my Spotswood clinic in Melbourne and via telehealth across Australia. I work with women through preconception, all three trimesters, and the postpartum period. Book a consultation. You can also read more about the fertility and pregnancy support I offer on my conditions treated page.
Frequently Asked Questions About Pregnancy Supplements
When should I start taking pregnancy supplements? Ideally, three months before you plan to conceive. This gives your body time to build adequate nutrient stores, particularly folate, and to address any deficiencies that could affect conception or early pregnancy. If you are already pregnant, start immediately. The sooner your nutrient status is optimised, the better.
Do I need to take a separate DHA supplement if my prenatal already contains omega-3? Check the dose. Many prenatal multivitamins contain only a small amount of DHA, often well below the 200 to 300mg recommended during pregnancy. If your prenatal contains less than that, a separate high-quality fish oil or algae-based DHA supplement is worth adding, particularly in the third trimester when brain development is most rapid.
Is it safe to take a probiotic during pregnancy? Yes. Probiotic supplementation during pregnancy is well studied and considered safe. The benefits for both maternal gut health and the baby's microbiome are significant. Choosing a practitioner-grade product with strains that are specifically studied in pregnancy gives you the most clinically useful outcome.
Why do I still feel iron-deficient even though I am taking iron supplements? Iron absorption depends on several factors, including the form of iron, what you take it with, and the state of your gut health. Non-haem iron from supplements and plant foods is less well absorbed than haem iron from meat, and certain foods, including tea, coffee, and calcium supplements taken at the same time can block absorption. If your iron levels are not responding to supplementation, it is worth investigating gut absorption and checking whether your supplement form needs to change.
What is the difference between folic acid and folate? Folic acid is the synthetic form found in most supermarket prenatal vitamins. Folate, or methylfolate, is the active form the body can use directly. A significant proportion of women carry MTHFR gene variants that impair the conversion of folic acid to active folate, which is why practitioner-grade prenatal supplements that use methylfolate are often more effective, particularly for women who have experienced pregnancy loss or difficulty conceiving.
Kylie Sartori is a degree-qualified naturopath based in Spotswood, Melbourne, specialising in gut health, fertility, pregnancy, and family wellbeing. She offers in-person consultations at her Spotswood clinic and telehealth appointments for clients across Australia.
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