What vitamins and minerals to take during pregnancy

All vitamins and minerals help the human body function as it should. That said, a few of these are particularly important for pregnant women: folic acid, iron, calcium, vitamin D, fibre, iodine, choline, and omega-3. They play an essential role in all stages of growth of the embryo and fetus.

Why take vitamin and mineral supplements?

Sometimes, a woman’s diet doesn’t provide enough of certain nutrients that play a crucial role in pregnancy. As such, pregnant women are advised to take a daily prenatal vitamin and mineral supplement. A multivitamin helps fill any nutritional gaps that a woman may have during her 9 months of pregnancy.

A good prenatal supplement should contain 0.4 mg to 1 mg of folic acid and 16 mg to 20 mg of iron. Quantities may vary according to the recommendations of the health care professional monitoring the pregnancy.

The Society of Obstetricians and Gynaecologists of Canada points out that, in addition to prenatal multivitamins, pregnant women may need to take iron supplements, particularly when they have an iron deficiency.

Folic acid (vitamin B9)

This vitamin is important, especially in early pregnancy. In the first days after conception, folic acid plays a vital role in the formation of baby’s spinal cord and brain.

If you wait until you’re pregnant to take a multivitamin, this crucial stage of development will have already passed. Health professionals therefore recommend that women start taking a multivitamin containing folic acid 2 to 3 months before conceiving. It’s also recommended that all women who can become pregnant, whether they intend to or not, should take a folic acid supplement every day.

Folic acid is involved in the formation of the brain and nervous system, new tissues, and blood cells. During pregnancy, folic acid deficiency can cause growth retardation, birth defects, and neural tube defects (including spina bifida). Severe physical or mental disabilities may occur as a result.

Pregnant women’s daily folic acid requirements range from 0.4 mg to 1 mg. Women who have a family or personal history of neural tube defects need an even higher dose.

In Canada and the United States, folic acid is added to white flour, and is usually added to corn flour and pasta. However, pasta made in Italy isn’t fortified with folic acid, so be sure to check the list of ingredients.

Iron

Iron is found in red blood cells. It allows these cells to capture oxygen from the lungs and transport it throughout the body and to the fetus through the placenta.

Pregnant women need more iron because their blood volume increases and they need to provide iron to their unborn baby. A baby’s iron stores at birth last for the first 6 months of life at most.

Adequate iron intake has many benefits during pregnancy. It reduces the risk of preterm birth, low birth weight, and infant mortality.

Iron deficiency can cause anemia, which can in turn cause fatigue and shortness of breath on exertion. Iron deficiency can be detected by a blood test. Vegetarian women and those who have close or multiple pregnancies are at greater risk of iron deficiency.

Other sources of iron

Some vegetables small amounts of iron, such as green vegetables (kale, spinach, asparagus, snow peas, etc.), beets, and skin-on potatoes. Eggs and nuts also contain iron.

However, iron from plant foods isn’t absorbed as well by the body as iron from meat, poultry, and fish. That’s why vegetarians must consume nearly twice as much iron to meet their needs.

How to promote iron absorption

When you eat plant foods that contain iron, the body needs vitamin C. It’s therefore recommended to serve them with a fruit or vegetable that’s rich in vitamin C (e.g., bell peppers, tomatoes, turnips, cauliflower, broccoli, sweet potatoes, Brussels sprouts, grapefruit, clementines, tangerines, strawberries, raspberries, kiwi, melons, mangoes).

Tea and coffee should be avoided during the meal and in the hour before and after it. Both beverages contain substances that interfere with iron and calcium absorption.

Calcium

The fetus needs calcium to build its skeleton. Calcium helps build bones and teeth. It also helps maintain good blood pressure during pregnancy.

If your diet isn’t rich enough in calcium, your body will deplete its own stores for the sake of the baby.

If you don’t eat enough calcium-rich foods, you may need to take supplements. Taking 500 g of calcium per day helps reduce the risk of preeclampsia (high blood pressure during pregnancy) in women with inadequate calcium intake. According to Health Canada, 63% of women aged 19 to 50 have an inadequate calcium intake. Talking to a nutritionist can help.

Vitamin D

Vitamin D works in tandem with calcium, increasing the absorption of calcium and strengthening bones. It’s also involved in cell growth and immune system function. Adequate vitamin D levels during pregnancy provide lifelong benefits to the mother and her child.

The sun is our main source of vitamin D. Our bodies manufacture it when exposed to sunlight. But in northern countries like Canada, people get less sun exposure between October and April. Vitamin D levels may therefore become insufficient during this period.

There are also certain foods that contain or are fortified with vitamin D. Even if you eat these vitamin D-containing foods, supplements may be necessary. Most prenatal multivitamins contain vitamin D.

Studies suggest that vitamin D supplementation may help pregnant women reduce their risk of preeclampsia, gestational diabetes, low birth weight, and more.

*It’s safe for pregnant women to eat canned light tuna. However, they should limit their consumption of fresh or frozen tuna and canned albacore tuna. For more information, see the Fish and mercury: Recommendations section of our Healthy eating during pregnancy fact sheet.

Omega-3 fatty acids

There’s mounting evidence that omega-3 fatty acids are extremely beneficial during pregnancy. These good fats contribute to the development of the baby and the mother’s health.

Omega-3 fatty acids play a role in the development of the baby’s brain and eyes. They have also been shown to lower the mother’s risk of depression throughout her pregnancy and after giving birth.

In general, people don’t get enough omega-3 fatty acids from their diet. For this reason, pregnant women are advised to eat at least two servings of fatty fish per week (200 to 350 g of cooked fish).

An analysis of 70 studies concluded that taking omega-3 supplements during pregnancy reduced the risk of preterm birth (before 37 weeks) and very preterm birth (before 34 weeks). Women with low-risk pregnancies, however, don’t stand to benefit from an omega-3 supplement. Eating fish is a better choice for these mothers-to-be. When omega-3 fatty acids are combined with other nutrients, they’re more beneficial.

*These fish are also low in mercury, a contaminant to be avoided during pregnancy.

Other sources of omega-3 fatty acids

Other foods contain omega-3s, including walnuts, canola oil, and flax or chia seeds. Some eggs are also enriched with omega-3.

These foods contain a different type of omega-3 than oily fish. Although our bodies can transform a small quantity of this omega-3 into the type found in oily fish, it isn’t enough to meet a woman’s needs during pregnancy.

Fibre

Fibre reduces the risk of constipation, which is common during pregnancy and is often caused by hormonal changes and iron supplements.

Eating fibre-rich foods every day and drinking plenty of water is essential to prevent or treat constipation. Consuming foods that are naturally high in fibre (such as those listed below) is more effective than eating foods that are enriched with concentrated fibre (such as oat bran or inulin).

Iodine

Iodine is a mineral that’s present in very small quantities in our body. It helps us produce thyroid hormones, which are essential for bone formation, muscle contractions, and heartbeats. They also help absorb nutrients.

Iodine also contributes to fetal brain growth, and a deficiency may lead to developmental disorders.

Table salt sold in Canada has been fortified with iodine for over 100 years. However, people are advised to use less salt nowadays, which has caused the population’s iodine intake to decline. Commercially processed foods—which are very salty—don’t contain iodine. The best solution is to cook at home as much as possible and add small pinches of salt here and there.

Choline

Choline is an essential nutrient for fetal brain development. It is believed to help prevent neural tube defects. It also helps the placenta function properly.

This nutrient is rarely included in supplements for pregnant women, so it’s important that they regularly eat foods rich in choline.

Vitamin B12

Vitamin B12 is essential for the production of red blood cells and the proper functioning of the baby’s nervous system. It works in conjunction with folic acid to make DNA (genetic material).

Since the vitamin is found almost exclusively in foods of animal origin, vegetarian women or those who eat very little meat, fish, eggs, or dairy products should pay special attention to their intake. It’s essential that they take a multivitamin that contains B12.

Vitamin B12 deficiency could impair a child’s cognitive functions and cause anemia in mother and child. It may also cause memory impairment and other permanent neurological problems in the mother.

Vitamins and minerals

Vitamin C, other B vitamins, zinc, magnesium, and several other vitamins and minerals also contribute to a healthy pregnancy. There is less mention of them because pregnant women who have a varied diet can easily get the necessary amounts. The nutrients we’ve talked about in this fact sheet can be more difficult to get from diet alone.

Things to keep in mind

• Taking a multivitamin containing folic acid is strongly recommended for at least 2 to 3 months before conception.
• Taking a prenatal multivitamin is advised throughout pregnancy.
• A varied diet is essential to provide the pregnant woman and her baby with all the nutrients they need.

Scientific review: Geneviève Mailhot, Ph.D., dietician nutritionist (DtP) Research and copywriting:The Naître et grandir team Updated: November 2025

Photos: GettyImages/Prostock-Studio and GettyImages/Marcela Vieira