Your Complete Guide to Taking Prenatal Vitamins

Whether you’re pregnant or thinking about getting pregnant, nutrition may be on your mind. Your body needs different nutrition before and during pregnancy. You won’t need many more calories at the beginning of pregnancy, but you will need more of many vitamins and minerals.

It can be difficult to meet these added needs with food alone—that’s where prenatal vitamins can help. They’re specifically designed to help you meet your increased nutrient needs and give your growing baby a strong start.

Before getting started, consult with your doctor about any changes to your diet and prenatal vitamin supplement plan.

Even if you’re eating a balanced diet, prenatal vitamin supplements are an important part of a healthy pregnancy. Prenatal vitamins are multivitamin/mineral supplements that are specifically made for pregnant women. They contain nutrients such as iron and folate that your baby and you will need before, during, and even after pregnancy.

You can get prenatal vitamins by prescription or at the drug store in chewable, gummy, and powdered forms. If the options seem overwhelming, or the vitamins irritate your stomach, talk to your doctor about which type of prenatal vitamin is best for you.

Essential nutrient support
Eating healthy foods during pregnancy is essential. Prenatal vitamins are designed to help fill any nutrition gaps in your diet—from the beginning of your pregnancy through breastfeeding. Read the Art of Eating guide for more on the role of prenatal vitamins before and during your pregnancy.

Reduced risk for complications and birth defects
Studies show that prenatal vitamins can help reduce premature birth, gestational diabetes, and preeclampsia (high blood pressure). They can also lower the risk for birth defects in the brain and spinal cord, like spina bifida.

It’s best to start taking prenatal vitamins when you know you’re trying to get pregnant. Clinical trials have shown benefits for women of childbearing age who begin supplementing with a prenatal multivitamin 4 weeks prior to conception and continue to supplement throughout pregnancy. This can significantly reduce the risk of having a child with a congenital birth defect, including neural tube defects and heart defects.

Nutrition for two
You’ve probably heard the expression “eating for two.” The reality is, the number of calories you’re consuming shouldn’t change much during your first two trimesters. What you really need is enough nutrients for two—and, with some nutrients, this means you need about 50% more.

It can be a tricky balance to get all the nutrients you need without overeating. Prenatal vitamins are a great way to help meet your and your baby’s need for nutrients without adding extra calories.

Learn more with our Guide to Pregnancy Weight.

See the latest US Dietary Guidelines(PDF, 30.6 MB) for calorie intake recommendations during pregnancy and breastfeeding. 

Multivitamins have some of the same vitamins and minerals, but prenatal vitamins include more folic acid and iron. Folic acid has been shown to help prevent serious birth defects of the brain and spinal cord. Iron supports your baby’s growth and brain development and helps prevent anemia in pregnant women.

Doubling your regular multivitamin intake isn’t recommended. This may provide too much of some nutrients and not enough of other important pregnancy nutrients. Also, some multivitamins do not include important trace minerals such as chromium, copper, molybdenum, manganese, and zinc.

It’s best to take a prenatal vitamin specifically designed for pregnant women and speak to your doctor about one that’s right for you.

Important Pregnancy Nutrients

• Folate supports your little one’s overall growth and development and may reduce the risk of birth defects
• Vitamin D and calcium help build baby’s bones and teeth
• DHA supports brain and eye development
• Iron, especially early in your pregnancy, helps to support your increasing blood supply

Most women of childbearing age do not get enough folate, vitamin E, and vitamin D, and big changes in your body begin right from conception. For instance, the placenta—the organ that supports baby’s growth and development—begins growing immediately. New blood cells also begin to form. Iron is important during this time because it helps support the increased red blood cells and blood volume that help grow the placenta.

The neural tube also forms very early in pregnancy. This is a hollow structure that will become your baby’s brain and spinal cord. Healthy neural tube formation requires folate. Without it, there’s a risk that the neural tube may not form properly.

If it’s not possible to start taking prenatal vitamins before conception, just make sure to take them when you find out you’re expecting.

The importance of the first trimester
You should take prenatal vitamins throughout your pregnancy. But they’re especially important to help fill nutrition gaps during the first trimester. Keep in mind a pregnant woman needs a higher amount of nutrients than a non-pregnant woman of the same age.

How long to take prenatal vitamins
Your doctor may recommend that you take prenatal vitamins even after your baby is born and while you're breastfeeding. This is to make sure you're getting the nutrients you need to replenish your nutrient stores and produce nutrient-rich milk for your new arrival.

Advice on timing
As with any multivitamin, the best time to take prenatal vitamins is with a meal. This is because fats in your food can help absorption of fat-soluble vitamins A, D, E, and K. Also, taking prenatal vitamins on an empty stomach can irritate your stomach and increase nausea.

Mom tip: To help decrease mild nausea, ask your doctor or pharmacist if you can take half the prenatal vitamin in the morning with breakfast and the other half later in the day with another meal or snack.

Look for these nutrients in your prenatal vitamins:

Folate (folic acid)
You may have heard about folate, or folic acid. Folate is the natural form of vitamin B₉ found in food, and folic acid is a synthetic form used in vitamins.

Folate is one of the most important nutrients during pregnancy. Getting the recommended daily intake of folate can help reduce the risk of birth defects of the brain and spine and supports rapidly growing cells and development of your baby and placenta. Green leafy vegetables, orange juice, beans, fortified cereals, enriched bread and pasta, and nuts are great natural sources of folate.

Iron
Pregnant women need about 1.5 times as much iron as those who aren’t pregnant. That’s because iron is used to make hemoglobin, which transports oxygen throughout your body and helps deliver blood and oxygen to your baby.

Iron is important for keeping up with your increasing blood supply during pregnancy. You can get more iron in your diet from lean red meat, poultry, fish, dried beans, peas, iron-fortified cereals, and prune juice.

Calcium
Calcium is very important for building your little one’s bones and teeth. It also helps baby develop a healthy heart, nerves and muscles, and a normal heart rhythm.

The best sources of calcium are dairy products such as milk, cheese, and yogurt. Fish with bones, such as sardines, and green leafy vegetables are also good sources. Those who are lactose intolerant may struggle with meeting their calcium needs from diet alone, but many milk substitutes are calcium fortified.

Vitamin D
Vitamin D helps build baby’s bones and teeth, supports calcium absorption, and promotes immune system health. Studies show that getting enough vitamin D during pregnancy can also help prevent heart disease and osteoporosis (bone loss) later in your life and reduce the risk of preterm birth.

Many people, including 40% to 60% of the US population and pregnant women, don’t get enough vitamin D. Some reasons for this are that few foods contain this vitamin and the increasing use of sunscreens. Keep your vitamin D levels up by getting plenty of sunlight by spending time outside, fortified milk, egg yolks, and fish with bones, such as salmon and sardines.

DHA
DHA is one of the omega-3 fatty acids that support your little one’s brain and eye development. Studies show that most women’s diets don’t include enough DHA.

Not all prenatal vitamins contain DHA, so make sure to check the label. You can also eat DHA-rich foods such as salmon, sardines, pollock, and DHA-fortified foods. Flax seed is a good plant-based option for omega-3, but the other sources mentioned are more effective. If you are breastfeeding, the level of DHA in your breast milk will also depend on your diet and supplement use.

Iodine
More than 23% of pregnant women in the US have been found to be deficient in iodine. This is partly because pregnant women need more iodine than nonpregnant women. This is also due to changes in the dairy industry which have resulted in reduced levels of iodine in milk—once a major source of iodine intake. In addition, there is a trend to use sea salt, which in most instances lacks iodine, and most restaurants and companies that make processed food do not use iodized salt. These factors combined have led to lower consumption of iodine.

Taking a prenatal vitamin that includes iodine can help you get enough of this important nutrient without increasing your sodium intake. Iodine is essential for regulating your thyroid hormone function during pregnancy. It’s also key for regulating baby’s metabolism and for the development of their brain and nervous system. You’ll find iodine in fish, iodized salt, and many dairy products.

What is needed in prenatal vitamins?
Use the chart below to find the daily recommended amounts of critical nutrients. See why they’re important and ways to add them to your diet.

Recommended Daily Nutrient Amounts—Pregnancy and Breastfeeding

A note about choline

Since most prenatal vitamins don’t contain choline, your doctor may recommend a supplement. Choline is an essential nutrient that plays a role in baby’s brain development.

For more information about the nutrients needed during pregnancy, read our prenatal nutrition guide.

Check your supplements
It’s true you need more nutrients now that you’re pregnant. But, if you begin taking a prenatal vitamin, check with your doctor first, as adding supplements could result in getting more than the recommended daily allowances of certain nutrients.

Nausea
If you experience nausea after taking your vitamins, try breaking them in half and take one half in the morning and one at night. Be sure to take them with a little bit of food.

Constipation
Constipation can be a normal side effect of pregnancy. Sometimes prenatal vitamins can cause constipation due to the iron content. Changes in your digestive system caused by pregnancy can also play a role in constipation. Eating foods that contain soluble fiber like oatmeal, apples, and brown rice—as well as drinking plenty of water—can help.

It’s recommended that you drink about ten 8-fluid-ounce glasses of water each day during pregnancy. Regular exercise can also help ease constipation. If you’re still having trouble, talk to your doctor about switching to a prenatal vitamin with less iron.

Vitamin B₆ for nausea
Some studies have shown that women who suffer from morning sickness have a lower level of vitamin B₆ in their blood. Since prenatal vitamins contain vitamin B₆, taking your prenatal vitamin may help to ease these feelings over time. Be sure to check the label and talk to your doctor.

Vitamin B₁₂ for vegetarians and vegans
Vegetarians and vegans will need to pay attention to vitamin B₁₂. This vitamin is found mainly in animal products like meat, fish, shellfish, eggs, and dairy. Check your supplements to see that they have an adequate amount of vitamin B₁₂.

If you are a vegetarian or vegan, make sure to include vitamin B₁₂-fortified foods like soy and rice beverages, breakfast cereals, and meat alternatives in your diet. If you’re following a vegetarian or vegan diet, you also may not be getting enough iron, vitamin D, vitamin E, and choline. Talk to your doctor about taking a supplement.

In most cases, your and your baby’s nutrition needs can be met with a healthy diet alone, though it may be difficult to meet your new, increased need for iron and folate. A prenatal vitamin can be a great way to fill any nutrition gaps. 

Check with your doctor to see which one is best for you. You should also look to wholesome, minimally processed foods as your best source for balanced nutrients in your diet.

Sources

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Mayo Clinic Staff. Prenatal vitamins: why they matter, how to choose. Mayo Clinic. Updated April 13, 2018. Accessed August 1, 2023.
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