Prenatal Vitamins 101: The Best Resource For Pregnant Women

pregnant woman

All mothers want their child to be happy and healthy, but this requires a considerable amount of effort on the mother’s part. They need to make sure they’re getting all the nutrients they need to help their baby fully develop.

It can be difficult - if not impossible - to get all of the required nutrients through daily intake of food. Because this is the case, prenatal vitamins play a massive role in the healthy development of a fetus.

What are Prenatal Vitamins?

Pregnancy comes with a long list of life changes that you may have never predicted. One of those elements is nutrition, and you’re probably facing some dietary requirements you’ve never encountered before.

You can get a lot of these vitamins and minerals through regular diet, but there will undoubtedly be some gaps there. This is where prenatal vitamins come into play. They can fill those gaps left by proper nutrition, and give you the best shot at keeping you and your baby healthy while you’re pregnant.

Do Women Really Need Prenatal Vitamins?

In short: yes.

Countless studies have determined the necessity of prenatal vitamins and their role in developing a happy, healthy child. We’ll get into some of the specifics of what ingredients are beneficial in a later section, as well as some of the science behind these claims.

Although all women and children will benefit from prenatal vitamins before, during, and sometimes after pregnancy, there are a few groups who require special attention. Some women with health concerns and dietary constraints will put their future children at greater risk by failing to take prenatal vitamins.

Since these vitamins are a way to supplement nutrition, they’re useful to everyone. The following groups, though, are in particular need of prenatal vitamins. They either can’t gain certain vitamins from their diet or have a natural predisposition that causes them to lose these essential vitamins at a fast rate.

Vegans and Vegetarians

Vegans and vegetarians, in particular, require supplementary vitamins and minerals before and during pregnancy. There are ways for those with a plant-based diet to get nutrients through their food, but it’s much more difficult for them than it is for omnivores.

One study took a look at vegetarian and low-meat eaters during pregnancy. It specifically looked at the vitamin B-12 in their body, which is an essential health component to a healthy pregnancy. It is important for pregnant women to monitor their blood sugar to ensure that there won't be any complication during pregnancy.

The study found that women who have been a vegetarian or vegan for a long period (more than three years) are more likely to have a B-12 deficiency. The study even claimed that recommendation of healthy vegetarian pregnancies needs to be reevaluated. (1)

While vegetarian diets can serve as a healthy way to go through pregnancy, there are some massive hurdles here. Vegetarians need to work harder to find essential vitamins and minerals that are more common in meat.

While it’s essential for all women to take prenatal vitamins, they’re especially necessary for vegetarian and vegan women. 

a plate of bow tie pasta and vegetables

Women Having Twins

Women who are having twins are another group who needs to take extra care with their prenatal vitamins. If a pregnant woman is eating for two, then a woman pregnant with twins is eating for three.

The two babies growing inside a woman’s womb need more calories, nutrition, and vitamins to develop healthily. After all, they fetuses are sharing all of the nutrients with each other, and the recommended dosage of nearly everything goes through the roof.

Women who are pregnant with twins need to eat more of everything, and vitamins and minerals are no exception. Twins are far more likely to become anemic from a lack of iron than their singleton counterpart. Likewise, they’re eight times more apt to face folate deficiency than singletons. (2)

Unfortunately, there isn’t as much evidence surrounding twin pregnancy as there is for singleton pregnancy (because twins are far rarer). Still, the recommendations persist that women who are expecting twins need to take extra care with their prenatal vitamins.

Medical outlets recommend that women who are pregnant with twins take twice the number of prenatal vitamins as women expecting one child. They may also be able to take single-dose vitamins that are high in folic acid and iron.

Make sure to check with your healthcare provider about proper prenatal nutrition if you’re pregnant with two or more children. You will almost always have to increase your prenatal vitamin intake.

Obese Women

Obese women who become pregnant are at an increased risk of several pregnancy complications. This group is more likely to encounter preeclampsia, gestational diabetes mellitus, and cesarean delivery. The same is the case for women who gain an unhealthy amount of weight during pregnancy.

The health of the woman is inherently tied to the health of the fetus, so obese women need to take extra care when protecting their unborn child’s development. The unhealthy amount of excess weight can lead to an increased risk of neural tube defects as well, making folic acid a must-have supplement before and during pregnancy. (3)

The study we cited above is worth a look if you are obese and considering becoming pregnant. There are a host of risk factors associated with obese pregnancy, and you can’t solve all of them with prenatal vitamins.

Women naturally gain weight during pregnancy, but women who are already obese will be safer if they lose weight before becoming pregnant. Those who can afford to lose weight before pregnancy should do so to avoid putting themselves and their unborn babies at a heightened risk for multiple pregnancy complications.

We’ll take a detailed look at the must-have prenatal nutrients in the next section, but folic acid is one of them. While this and other nutrients will assist the development of any baby, it’s particularly important for obese women who face an increased risk of neural tube defects.

Women with Hypertension

Hypertension is difficult to prevent, but like obesity, it can lead to a long list of complications when it comes to pregnancy. This group encounters risks like placental abruption, intrauterine growth restriction, premature delivery, and other birth and pregnancy risks that affect both mother and child. (4)

While women need to address many of these problems with their healthcare professional, they can reduce some of the risks of pregnancy by taking prenatal vitamins. For instance, some women with hypertension experience a decrease in blood flow to the placenta.

A low blood flow means the baby won’t receive as much oxygen and nutrients as they need. You will have to talk to your doctor about the proper steps you need to take here, but taking prenatal vitamins will ensure your baby gets at least some of the nutrients they need.

Of course, you should take extra steps to be careful if you have chronic hypertension and become pregnant. Make sure any blood pressure medication you’re purchasing is safe for the baby, and check with your doctor if you’re unsure of any steps you need to take.

pregnant woman lying in bed and resting


Everyone knows that it’s unhealthy to smoke during pregnancy. Smoking rates in women who are pregnant have dropped substantially over recent years, but they still aren’t 0%. Unfortunately, women who choose to smoke while they’re pregnant are putting their babies directly in harm’s way.

What you might not know, however, is that smoking in the early stages of pregnancy and during lactation can affect as well. A lot of women don’t realize that they are pregnant for a month or more and continue to smoke. If the woman is a smoker, they would have no reason to think they are putting anyone but themselves at risk at this time.

Smoking after pregnancy can affect the child as well. If the mother chooses to breastfeed her child while she’s still smoking, she will pass the nicotine from her body to the body of her infant, increasing their risk of complications in the long and short-term. (5)

Prenatal vitamins aren’t the cure for complications surrounding smoking and pregnancy, but they can offer assistance. If you have been smoking during the early stages, for instance, taking prenatal vitamins will help ensure there isn’t any additional neural tube damage, which can lead to problems later in life.

Must Have Prenatal Nutrients

There are countless brands of prenatal vitamins out there. Just like any multivitamins on the market, there are some brands with superior ingredients to others. Despite this fact, most prenatal vitamins will include the essentials like iron and folic acid. These two are standard, and you should never purchase a prenatal vitamin without them.

In this section, we’ll take a look at what you should consider before choosing a prenatal vitamin. Your doctor may be able to give you a recommendation, but it’s a good idea to complete your own research on this topic.

Look for prenatal vitamin brands that include all of the following nutrients. The list below will give you nearly everything you need to aid the development of your unborn or newborn child.

Folic Acid

Folic acid is the first and most critical ingredient you should look for in prenatal vitamins. This ingredient is probably the most common, and you likely won’t find too many (if any) brands that sell prenatal vitamins without folic acid.

Folic acid is linked to a host of health benefits and preventive measures for unborn children. The advantage with the most scientific support behind folic acid is in the development of the neural tube.

The neural tube begins to develop during the first month of pregnancy, which is why it’s so important to start taking prenatal vitamins before you know you’re pregnant (more on this below). While women need this nutrient throughout their life, it’s even more important during pregnancy to meet the fetus needs.

The unborn baby requires folic acid to develop, which means the mother has to ingest more than they ever have before. Unfortunately, folic acid in its natural state - folate - isn’t as easy to find and digest as it is in its supplemental form.

You can find folate in green, leafy vegetables. Eating folate-rich foods will help your body metabolize more folate than in the past, but most pregnant women don’t consume enough folate in their diet to suffice when it comes to fetus development.

This is where prenatal vitamins present themselves. Almost every prenatal vitamin you find will contain folic acid, which will supplement your dietary gaps and make sure your child gets all the folate they require.

Studies have linked folic acid to the ability to prevent congenital heart defects and neural tube development - both of which can be devastating to an unborn baby. Recent research has even linked folic acid to protection against preterm birth, though more studies need to be completed before they can say for sure. (6)

vitamins in capsule hold in hand


Iron is another ingredient that you’ll find in almost every prenatal vitamin. Iron and folic acid are similarly important because it’s next to impossible to obtain the required amount of these nutrients through food. You can eat iron-rich foods like poultry and fish, but this won’t give you enough iron to pass on to your fetus.

As we stated in the section above, vegetarians and vegans are particularly susceptible to iron deficiency during pregnancy. They often don’t get as much iron from their diet as a meat eater, and therefore need even more supplementation in their prenatal vitamins. These women should talk to their doctor and explore the possibility of taking high-iron pregnancy multivitamins.

The iron requirement changes throughout the stages of pregnancy. During the first trimester, iron requirements are relatively low because of the size of the fetus and the lack of menstruation. Stopping menstruation causes a natural spike in iron, so the small fetus will likely get enough iron from their mother’s diet.

After the second trimester and beyond, the iron requirements start to rise. As the baby grows, they require more iron, and their needs eventually surpass the realistic amount someone can obtain through iron-rich foods. (7)

Iron is essential in preventing anemia, which can occur when someone doesn’t have enough iron in their blood. Efforts to avoid anemia have increased across the globe in recent years, and prenatal vitamins play a huge role here.


Calcium is another must-have ingredient for prenatal vitamins. This nutrient plays a role in both the health of the mother and the health of her child. Calcium is especially important for keeping a mother’s bones strong if they are deficient in calcium before they become pregnant.

A growing fetus requires calcium, and they continue to need calcium after their born. They get this calcium through their mother when they’re in the womb, and through breast milk, after they are born. (8)

A lack of calcium can lead to a host of problems for both mother and child, and without proper supplementation, could lead to deficiencies for all parties involved. (9)

You can obtain calcium through your diet by eating dairy products, but this isn’t enough for a lot of pregnant women. Like all of the ingredients you see in this list, the essential amount of calcium is difficult to reach through diet alone.

Vitamin D

Calcium and vitamin D go hand-in-hand in preventing health issues for children and their mothers. A deficiency in vitamin D will lead to reduced calcium levels because vitamin D allows the body to absorb calcium more effectively.

A lack of vitamin D will put you and your child at a greater risk of developing a calcium deficiency. The combination of these two can lead to a bone density issue that could impact a child for years.

There have been other claims about vitamin D’s preventative ability, but more research needs to be completed to conclude. Some of the other theorized benefits of vitamin D include preventing low birth rate and preterm birth. (10)

Vitamin D is particularly important in supplement form because so many people in the Western world are already vitamin D deficiency. We can receive some vitamin D through diet, but we absorb most of the vitamin through exposure to the sun, which doesn’t happen often enough for most.

Vitamin A

Vitamin A is another essential vitamin that plays a role in childhood development and maternal health. One review took a look at studies relating to vitamin A supplementation in poor countries and found a strong correlation between vitamin A supplementation and prevention of maternal mortality. (11)

Vitamin A is also associated with the development of a healthy baby’s circulatory, respiratory, and central nervous system development.

Vitamin A is a bit more nuanced than some of the other nutrients on this list. You can have too much vitamin A, so check with your doctor to make sure your prenatal vitamins have the right amount of vitamin A for you and your developing child.

When Should You Start Taking Prenatal Vitamins?

Prenatal vitamins play a critical role in preventing birth defects and ensuring the health of your baby. There has been a lot of debate over the efficacy of prenatal vitamins and when women should start taking them. Over the years, though, the scientific community has landed on somewhat of an agreement: as soon as possible. (12)

You should start taking prenatal vitamins as soon as you learn that you’re pregnant. If you suspect you might be pregnant, it’s a good idea to start taking them before you even confirm the pregnancy.

In fact, many health institutions advise that you start taking prenatal vitamins at least two to three months before you become pregnant. Some even recommend that all women of reproductive age take these vitamins.

There are studies that support this recommendation, so it’s smart to start laying the groundwork for pregnancy in your body before it actually happens. (13)

The reason early intervention is critical here is that the baby’s neural tube starts to develop during the first month of pregnancy. The neural tube later develops into the brain and spinal cord, so it’s essential that it stays healthy during even the earliest stages of development.

A lot of women might not even realize they’re pregnant for the first month, and won’t know that it’s time to start taking prenatal vitamins.

Of course, this recommendation is only for women who plan on becoming pregnant. There’s no reason to take prenatal vitamins if you are taking active steps to avoid pregnancy, although you can never be 100% sure.

How Long Should You Take Prenatal Vitamins?

Now you know that healthcare providers recommend taking prenatal vitamins before and during pregnancy, but it can be a bit confusing to know when it’s time to stop. The answer is different depending on whether or not you intend to breastfeed your newborn child.

If you don’t plan on breastfeeding - or are unable to breastfeed for one reason or another - you can stop taking prenatal vitamins once you have your child. While a boost in essential nutrients will be beneficial for your health, the impact on the baby ends there.

Those who are breastfeeding, however, should continue to take prenatal vitamins as long as they are breastfeeding their child. Breastfeeding requires women to proceed to pass their nutrition onto their child and therefore should make sure they always have enough iron. Folic acid, and other vitamins and minerals that will keep their child healthy.

While breastfeeding women don’t need as much of certain nutrients as pregnant women, they still need more than women who aren’t pregnant or breastfeeding. They need about as much niacin, thiamin, iron, and calcium as pregnant women, and actually, need more essential vitamins than pregnant women. Studies show that lactating women need more Vitamin C, B12, B6, and E than pregnant women. (14)

Talk to your doctor about the best multivitamin option when you’re lactating, but they’ll probably tell you to continue to take your prenatal vitamins. This process keeps everything simpler and allows you and your baby to receive the nutrients you need.

Are There Any Side Effects?

Most women don’t experience any side effects of prenatal vitamins, but that doesn’t mean you’ll be free from them. Some women report having an upset stomach when they take these vitamins, but this is easily managed by making sure you take them on a full stomach.

The other side effects are stool related. Women commonly experience constipation, dark stools, and diarrhea when they take prenatal vitamins.

The culprit behind these side effects is iron. A 1994 study observed the effect iron had on blood donors, noting that those taking iron supplements experienced constipation at a higher rate than the control group. (15)

Iron usually causes these adverse reactions in high doses, so prenatal vitamins shouldn’t cause side effects for everyone. You can manage these symptoms by drinking a lot of water, eating fiber, increasing physical activity (as long as your doctor approves), and purchasing stool softeners.

There’s a chance you’re purchasing the wrong prenatal vitamins as well. There are a lot of brands that target women with iron deficiency, and their vitamins have a higher concentration of iron than some of the others you’ll find.

If you have normal iron levels, you only need some supplementation instead of a massive dose. Check with your healthcare provider on this issue, but choosing a prenatal vitamin that’s lower in iron might alleviate some of the side effects you experience.

Either way, these side effects are a small price to pay for a healthy, happy baby. Talk to your doctor if you’re experiencing any of these side effects, and they should be able to recommend a solution that’s healthy for you and your baby.

woman carrying baby child

Childhood Obesity

There have been a few claims that prenatal vitamins are harmful to the child because they can trigger an increased risk of obesity. The evidence that supports this claim is almost entirely from the results of studies on animals. Until recently, the relationship between obesity and prenatal vitamins in human babies had little research behind it.

While this condition would certainly be a concern if it were true, the evidence doesn’t back up this kind of a claim. A 2013 study observed the relationship between obesity and prenatal vitamins and found that none existed. This is one of the cases where multivitamins affected animals differently than they affect humans. (16)

The study also found that adult abdominal adiposity wasn’t related to prenatal multivitamins either. Unless there is some more groundbreaking research in the future, it would appear that prenatal vitamins are nothing but positive for the development of unborn and breastfeeding babies.


It’s near impossible for a pregnant woman to get all of the required nutrients through diet alone. A growing baby needs too many nutrients from their mother, and meeting these requirements almost always requires supplementation.

This is especially the case when the mother has previous health conditions or dietary restrictions that will limit the number of nutrients they pass to their baby. Certain nutrients like iron and folate are particularly important, and can’t realistically be obtained through even the best pregnancy diet.

Prenatal vitamins play an important role in the health of both mother and child. Make sure you check the labels carefully, though, and observe our five must-have ingredients.


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