The 7 Best Iron Supplements for Pregnancy of 2023

Key Specs:
Form: Tablet | Type: Iron sulfate | Dose: 45 mg | Recommended Use: Take 1 tablet daily

How Much Iron Do You Need During Pregnancy?

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on June 1, 2022

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Iron during pregnancy is absolutely essential. And it’s easy — and oh so important — to get enough of this vital nutrient without even breaking a sweat.

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• Why is iron important during pregnancy?
• How much iron do pregnant women need?
• Best iron-rich foods for pregnant women
• Should you take iron supplements during pregnancy?

Pumping iron isn’t just for the gym. You can — and should — pump it up in your pregnancy diet, too. Iron is essential during pregnancy to support your baby’s developing blood supply, as well as your own.

The mineral is so vital for baby’s growth, in fact, that your recommended daily intake nearly doubles when you’re expecting. Having low iron stores can increase your risk of developing anemia, and severe iron deficiency may lead to low birthweight or premature birth.

With that in mind, is it necessary to take iron supplements when you’re pregnant? Here’s everything moms-to-be need to know about iron during pregnancy, including how to fill up on iron-rich food sources and how to know if supplementary iron is something you need.

Why is iron important during pregnancy?

It might seem counterintuitive that you need more iron during pregnancy considering 70 percent of iron is found in red blood cells — and you’re no longer losing blood each month during your menstrual cycle.

But your iron needs actually jump during pregnancy because your body produces more blood — to deliver oxygen to your growing baby and because you’re growing, too. Iron is also important in fetal brain development.

Having low iron levels can put you at risk for anemia, especially during the second half of your pregnancy.

How much iron do pregnant women need?

Pregnant women need 27 milligrams of iron per day (compared to 18 milligrams for adult women 19 to 50 years old who are not expecting).

Most prenatal vitamins include enough iron to cover that increase, but iron-deficiency anemia is common in pregnancy due to the increased demand for blood production. Luckily, it’s easy to prevent by filling your plate with plenty of iron-rich foods and, if your practitioner recommends one, with the help of a daily iron supplement.

More Healthy Eating Tips

Best iron-rich foods for pregnant women

The most easily absorbed sources of dietary iron (heme iron) include lean meat, poultry and fish. Non-animal (non-heme) sources are still beneficial, however, and you can enhance their uptake by consuming them alongside vitamin C-rich foods.

Best heme iron-rich food sources

If you’re looking to pump up the iron in your diet (and you’re not vegetarian or vegan), try adding these iron-filled foods to the menu:

• Canned sardines: 2.4 mg per 3 ounces
• Braised beef: 2 mg per 3 ounces
• Chicken: 1 mg per 3 ounces
• Eggs: 1 mg per 1 hard-boiled egg

Best non-heme iron-rich food sources

If you’re vegan or vegetarian — or just trying to eat more plant-based foods — these options will get more iron on your plate:

• Fortified breakfast cereals: 18 mg per serving
• White beans: 8 mg per cup canned
• Lentils: 3 mg per ½ cup boiled
• Spinach: 3 mg per ½ cup boiled
• Firm tofu: 3 mg per ½ cup
• Dark chocolate: 2 mg per ounce
• Tomatoes: 2 mg per ½ cup canned and stewed
• Kidney beans: 2 mg per ½ cup canned
• Cashews: 2 mg in 18 nuts

Should you take iron supplements during pregnancy?

An iron-containing prenatal vitamin in combination with sufficient dietary sources of iron throughout the day can provide many pregnant women with adequate amounts of the mineral. But iron-deficiency anemia is common, particularly after week 20 of pregnancy, and some moms-to-be do need a daily iron supplement in addition to their prenatal.

A blood test can check your iron levels and determine if you might need to take iron tablets during pregnancy that go beyond what’s supplied in your prenatal.

Anyone can develop anemia, but vegans and vegetarians have a higher risk, as do women carrying multiples, or those who have had back-to-back pregnancies or severe morning sickness. If you fall into one of those categories and notice symptoms of anemia (such as feeling fatigued, dizzy or breathless), ask your doctor if you might need an iron supplement.

Iron supplements come in various forms and amounts. Because iron can cause nausea and constipation, your practitioner may suggest slow release capsules or a different form of iron (like iron bisglycinate) that’s easier on the stomach.

If your doctor has also recommended supplementary calcium (or there’s calcium in your prenatal vitamin), you shouldn’t take it at the same time as an iron supplement, since calcium can interfere with iron absorption. Instead, plan on taking these supplements at least two hours apart.

The bottom line: For most women, iron supplementation is safe during pregnancy. However, not every mom-to-be needs extra iron, especially since the mineral is already found in most prenatal vitamins and certain common foods. As always, talk to your practitioner before adding any new supplements to your diet.

From the What to Expect editorial team and Heidi Murkoff, author of What to Expect When You’re Expecting. What to Expect follows strict reporting guidelines and uses only credible sources, such as peer-reviewed studies, academic research institutions and highly respected health organizations. Learn how we keep our content accurate and up-to-date by reading our medical review and editorial policy.

View Sources

• What to Expect When You’re Expecting, 5th edition, Heidi Murkoff.
• WhatToExpect.com, How to Prevent and Treat Anemia in Pregnancy, April 2021.
• American College of Obstetricians and Gynecologists, Nutrition During Pregnancy, March 2022.
• Rachel Fine, R.D., New York, NY.
• Food and Drug Administration, Advice About Eating Fish for Those Who Might Become or Are Pregnant or Breastfeeding and Children Ages 1–11 Years, February 2022.
• Tarun Jain, M.D., Northwestern Medicine Fertility and Reproductive Medicine, Oak Brook, IL, and Member of the What to Expect Medical Review Board.
• National Institutes of Health, Office of Dietary Supplements, Iron, April 2022.
• National Institutes of Health, National Library of Medicine, Iron Supplementation During Pregnancy and Infancy: Uncertainties and Implications for Research and Policy, December 2017.
• National Institutes of Health, National Library of Medicine, Iron Homeostasis During Pregnancy, December 2017.
• University of California San Francisco Health, Hemoglobin and Functions of Iron.
• U.S. Department of Agriculture, FoodData Central.

The 7 Best Iron Supplements for Pregnancy of 2023

Rich Scherr is a seasoned journalist who has covered technology, finance, sports, and lifestyle.

Verywell Family / Marcus Millan

Our bodies need iron in our blood to deliver oxygen to every cell and for proper functioning of our organ systems. Iron is especially important during periods of intense growth and development, such as pregnancy, and you could easily become deficient in iron during that phase of life. Iron needs are increased during pregnancy, because a pregnant woman’s blood volume expands significantly in order to maintain proper circulation and to deliver sufficient oxygen to her own tissues, as well as the placenta and baby.

Iron deficiency can increase an infant’s risk of low birthweight, premature birth, low iron stores, and impaired cognitive and behavioral development. It is estimated that 18 percent of pregnant women are iron deficient, with the prevalence increasing as pregnancy progresses. Iron supplementation can be an effective strategy to reduce the risk of iron deficiency anemia during pregnancy.

In order to recommend the best iron supplements for pregnancy, our prenatal dietitian combed through the latest research, interviewed other dietitians who specialize in nutrition during pregnancy, and used her own experience making recommendations to her clients. It is most important to consider the form and dose of iron to meet your needs and to select options that have been third-party tested for purity and potency.

For women who have blood transfusions or the condition hemochromatosis, iron supplements may not be beneficial. These supplements may also decrease absorption of medications like Levodopa, levothyroxine or proton pump inhibitors.

Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs, and to find out what dosage to take.

Our Top Picks
Best Overall:
Best for Preconception and Postpartum:
Best for Nausea and Digestion:
Best Budget:
Best Liquid:
Best High Dose:
Best Slow Release:
In This Article

Best Overall

Thorne Iron Bisglycinate

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• ConsumerLab.com approved
• Well-tolerated form of iron
• Provides an adequate dose of iron for pregnancy

• May not be enough to correct deficiency

Thorne’s Iron Bisglycinate checks all of the boxes for a quality prenatal supplement: It’s third-party tested and well-tolerated, and it provides the right amount to meet many pregnant women’s needs. We love that Thorne’s Iron supplement utilizes a form of iron that will not cause more nausea or constipation during pregnancy than you may already have. Bisglycinate means that the iron is bound to the amino acid glycine, which also ensures optimal absorption. It can help prevent iron-deficiency anemia in pregnancy just as well as other forms of iron.

The RDA for pregnancy is 27 mg of iron, and Thorne’s Iron Bisglycinate provides 25 mg. So, even if your diet is very low in iron from foods, this supplement would be a helpful tool to help meet your needs and prevent or help treat anemia in pregnancy.

This particular supplement is ConsumerLab.com approved and NSF Certified for Sport, so you can trust that it has been tested for purity, quality, and safety. It is gluten free, dairy free, and soy free, and it uses only natural flavorings and colorings. Take note that if you already have a more substantial iron deficiency, a healthcare provider may recommend a higher dose of iron than this supplement provides, or they may recommend taking multiple capsules. Please only do so under the supervision of a healthcare provider.

Price at time of publication: $13 ($0.22 per serving)

Key Specs:
Form: Capsule | Type: Iron bisglycinate | Dose: 25 mg | Recommended Use: Once daily with a meal

Best for Preconception and Postpartum

Needed Iron for Prenatal, Pregnancy, Breastfeeding, Postpartum

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• Well tolerated form of iron
• Third-party tested
• Flexible dosing

• More expensive for higher dosing

One reason why iron deficiency anemia can develop in pregnancy could be related to poor iron intake or low levels of iron prior to even becoming pregnant. For women who are vegetarian or vegan, or who have experienced heavy or irregular menstrual cycles, iron levels might be quite low. So, in those situations, it may make sense to take an iron supplement before you get pregnant. It also may be beneficial after giving birth. Even though the RDA for iron decreases during lactation, labor and delivery can result in substantial blood loss, so continuing with an iron supplement postpartum might be beneficial.

We love Needed Prenatal Iron as a preconception and postpartum option because of its flexible dosing and form. One Needed iron capsule contains 13.5 mg of iron bisglycinate. If you feel the need to create a good foundation of iron stores going into pregnancy, taking one pill daily would be a good place to start, as it’s not a very high dose. After birth, one or two pills per day would be recommended to replenish blood losses during the first six weeks after birth, but then you could decrease to one pill to easily meet the RDA for lactation, which is 9 mg.

Of course, this could be a great option during pregnancy as well, as you could simply take one to two pills daily, depending on your diet and iron needs. The Needed website even provides a chart that you could reference to determine your dose if you know your ferritin levels.

While not tested from NSF, USP, or ConsumerLab.com, Needed states their products do undergo third-party testing. Their supplements are vegan, allergen-free, non-GMO, and free of preservatives and additives. Needed is a woman-owned company that was started out of the founders’ personal nutrition and fertility journeys.

Price at time of publication: $20 ($0.33 per capsule)

Key Specs:
Form: Capsule | Type: Iron bisglycinate | Dose: 13.5 mg | Recommended Use: One to four capsules daily

Form: capsule | Type: iron bisglycinate | Dose: 13.5 mg | Recommended use: one to four capsules daily

Best for Nausea and Digestion

New Chapter Iron Complex Tablets

Courtesy of Amazon

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• Certified gluten-free
• Lower dose of iron may be better tolerated
• Digestive support blend may benefit some people

• Contains ingredients that may overlap with a prenatal vitamin
• Final product not third-party verified for purity and potency

Iron supplements are notorious for being hard on the digestive system, especially when taken on an empty stomach. If you have iron-deficiency anemia during pregnancy, and are suffering from morning sickness, vomiting, bloating, or heartburn, choosing a well-tolerated iron supplement will be extra important. We love New Chapter’s Fermented Iron Complex, because it takes all of this into consideration.

New Chapter’s iron complex is NSF gluten-free certified, Non-GMO Project verified, Kosher, and 100% vegetarian. It’s worth noting that while New Chapter reassures consumers that it conducts third party testing on ingredients, not all of their final products are tested for purity and potency, and we couldn’t find any information on third-party testing of this product.

New Chapter’s iron complex contains a lower dose of iron—only 9 mg—as ferrous sulfate, which typically can cause some GI upset, but at such a low dose that the risk is minimized. Plus, this supplement contains a digestive support blend of aloe, peppermint, cardamom, coriander, and artichoke, plus ginger and turmeric, which, for some, may help ease the constipation and nausea caused by the iron or general pregnancy symptoms.

Because of these supportive ingredients, a pregnant woman could take this iron complex with food or on an empty stomach. You may want to check with a healthcare professional before taking this supplement to make sure these extra digestive support ingredients are right for you.

Be advised that this complex also includes vitamin C, vitamin E, folate, vitamin B12, and zinc, which are all also likely included in your prenatal vitamin. Many of these nutrients will help ensure optimal absorption of this plant-sourced iron, but you should check with a healthcare provider about the total dosing of each of these micronutrients if you continue to take both your prenatal multivitamin and this iron complex.

Price at time of publication: $37 ($0.63 per serving)

Key Specs:
Form: Tablet | Type: Iron fumarate from ferment media | Dose: 9 mg | Recommended Use: One tablet daily with or without food

Best Budget

CVS Health Ferrous Gluconate Iron 27 mg Tablets

• Third-party tested
• Budget-friendly
• One tablet serving

• Low amount of elemental iron
• May cause GI upset

Many pregnant woman make substantial investments in their prenatal vitamin regimens, so, if you have to add an additional iron supplement, you may want to seek out a budget-friendly choice.

Fortunately, the CVS Health Ferrous Gluconate is a budget-friendly option but does not skimp on quality. CVS Pharmacy supplements abide by their Tested to be Trusted standards, which requires third-party testing by one of the major verification experts. This supplement contains the amount of iron as listed and does not exceed limits for heavy metals, pesticides, and microbial or other contaminants.

You can purchase this supplement at your local CVS retailer, or online, for only a few cents per tablet. The supply is 100 tablets, so it would last through your entire third trimester, which is a common period when iron deficiency can show up in pregnancy.

The form of iron in this supplement is ferrous gluconate. This form of iron does contain less elemental iron than the commonly found ferrous sulfate, and so a higher dose may ultimately be needed to correct for a deficiency. The gluconate form can be known to cause more gastrointestinal (GI) upset. For best results, we recommend taking it with food.

Price at time of publication: $9 ($0.09 per serving)

Key Specs:
Form: Tablet | Type: Iron gluconate | Dose: 27mg | Recommended Use: One tablet daily with food

Best Liquid

Mary Ruth’s Prenatal and Postnatal Liquid Iron

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• Easy to take
• Well-absorbed form of iron
• Sugar-free
• Third-party tested

• More expensive

Tired of taking prenatal vitamin pills? It might be time to explore a liquid option. Mary Ruth’s is a well-known supplement brand that makes vegan supplements for all stages of life. It is non-GMO, free of all major allergens, and sugar-free, which can sometimes be hard to come by in a liquid supplement. Another thing we like is that Mary Ruth’s conducts third-party testing on all of its products for ingredient amounts, contaminants, and heavy metals.

This liquid iron uses iron bisglycinate in the form of Ferrochel. Ferrochel iron is known to be “ionically neutral,” which means it does not compete with other nutrients for absorption. That is especially important for a pregnant woman who is taking other vitamins and minerals that typically interact with iron. You simply need to take 1 tablespoon daily during pregnancy, or 1/3 tablespoon during lactation. The pleasant berry flavor, which comes from natural flavors and stevia extract, allows you to take it on its own or mix it in with water.

Price at time of publication: $36 ($1.20 per serving)

Key Specs:
Form: Liquid | Type: Iron bisglycinate from Ferrochel | Dose: 27 mg | Recommended Use: Take 1 Tbsp daily

Best High Dose

Nature Made Iron 65 mg Tablets

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• USP verified and ConsumerLab.com top pick
• Effective for treating deficiency
• Small tablet size
• Budget-friendly

• May cause gastrointestinal upset

For some pregnant woman, iron deficiency can be so severe that high dose supplementation, or even iron transfusions, are needed. Before exploring the latter option, a healthcare professional may recommend taking a high-dose iron supplement first. We love Nature Made Iron 65 mg for this situation, because it comes from a trusted supplement brand that ensures third-party testing. In fact, this iron supplement is ConsumerLab.com approved and USP certified.

The RDA for iron during pregnancy is 27 mg, but for anyone who is carrying twins, triplets, or quads, the needs for iron increase dramatically—usually 30 mg for the first trimester and then 60 mg for the second and third trimesters. This Nature Made supplement is high-dose, supplying 65 mg of iron, so it would be a great option for treating deficiency in a singleton pregnancy or meeting the needs of pregnant women who are carrying multiples. The one catch is that the form of iron is ferrous sulfate, which means it may cause some to have gastrointestinal discomfort. To reduce discomfort, we suggest taking this small tablet with a meal.

Price at time of publication: $10 ($0.05 per serving)

Key Specs:
Form: Tablet | Type: Iron sulfate | Dose: 65 mg | Recommended Use: Take 1 tablet daily with water and a meal

Best Slow Release

Slow Fe Iron Tablets

Courtesy of Amazon

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• ConsumerLab.com approved
• Controlled delivery system to ease digestive upset
• Provides a high dose of iron

• Contains artificial colorings

Ferrous sulfate is arguably the most commonly found form of iron used in supplements due to its absorbability and affordability, but it does not sit well with everyone who takes it. Thankfully, Slow Fe has designed a ferrous sulfate pill that uses a controlled delivery system so as not to overload the GI system and cause nausea or abdominal discomfort. We also appreciate that this supplement is ConsumerLab.com-approved and was included on their Top Picks list as a good choice for a high-dose iron supplement. Each pill contains 45 mg of elemental iron, which is equivalent to 142 mg of ferrous sulfate.

If you are looking for a supplement that limits the use of artificial ingredients, Slow Fe might not be the one for you. Among the ingredients list, you will find artificial colorings and some preservatives that other high-dose iron supplements do not contain. One of the colorants, red 40 lake, is generally considered safe to use, although research on its consumption during pregnancy is limited.

Price at time of publication: $16 ($0.27 per serving)

Key Specs:
Form: Tablet | Type: Iron sulfate | Dose: 45 mg | Recommended Use: Take 1 tablet daily

Is an Iron Supplement Beneficial for Pregnancy?

You may notice that most prenatal vitamins do not contain iron, and you might be asking yourself, “Do I also need to be supplementing with additional iron?” Ayla Barmmer, MS, RD, LDN, founder and CEO of FullWell and owner of Boston Functional Nutrition, recommends getting your iron levels checked before deciding whether or not to add an iron supplement. “Anyone who has had significant blood loss before pregnancy—like heavy menstrual periods, surgery, or frequent blood donations—may need to supplement. Athletes tend to burn through their iron stores faster than non-athletes, so they may need to supplement, too.”

There are some other groups that will also likely benefit from an iron supplement. “[Pregnant women] with celiac disease, inflammatory bowel disease, resections, hemorrhoids, or bariatric surgery, may have an increased risk of iron loss and may have a more challenging time absorbing iron,” Barmmer says.

Since we get most of our heme-iron, which is the form best absorbed by the body, from animal foods, McKenzie Caldwell, MPH, RDN, creator of the body-positive fertility and prenatal nutrition program Fully Nourished Pregnancy says that “folks who eat a vegetarian or vegan diet, or who experience meat aversions in pregnancy,” will likely need to supplement, as well.

Who May Not Benefit from Iron Supplements in Pregnancy

Typically, if you have normal iron levels before pregnancy, and continue to maintain normal levels as pregnancy progresses, you will not need to supplement. Barmmer cautions against iron supplements for women who have blood transfusions or have the condition hemachromatosis, which can lead to an over-accumulation of iron in the body.

Iron supplements may decrease the absorption of medications such as Levodopa, levothyroxine, or proton pump inhibitors, all of which may be taken during pregnancy, so always consult with a healthcare provider about any potential interactions before taking an iron supplement.

How We Select Supplements

Our team works hard to be transparent about why we recommend certain supplements. You can read more about our dietary supplement methodology here.

We support supplements that are evidence-based and rooted in science, and we value certain product attributes that we find to be associated with the highest-quality products. We prioritize products that are third-party tested and certified by one of three independent, third party certifiers: USP, NSF, or ConsumerLab.com.

It’s important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend.

We also spoke to McKenzie Caldwell, MPH, RDN, creator of the body-positive fertility and prenatal nutrition program Fully Nourished Pregnancy, and Ayla Barmmer, MS, RD, LDN, founder and CEO of FullWell and owner of Boston Functional Nutrition, to provide further insight.

What to Look For

Third-Party Testing

Supplements that are third-party tested are sent to a lab where they are tested to ensure that they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note:

1. Third-party testing does not test to see whether a product is effective or safe for everyone, and it does not ensure that the supplement will not interact with other supplements or medications.
2. Not all third-party testing is created equal. It is not uncommon for supplement companies to pay labs for certificates after conducting minimal to no testing.
3. The third party certifications we trust are: ConsumerLab, NSF, and USP. However, these certifications are difficult to obtain and/or expensive for manufacturers, so many companies choose not to get their products tested by one of these three organizations.
4. Sometimes products tested by these three companies are more expensive, to try to offset the cost they pay for certification.
5. Just because a supplement is not tested by one of these three companies, it does not mean it’s a bad product. We recommend doing some research on the reputability of the manufacturer, and calling up the manufacturer and its testing lab to determine their protocols and decide whether you feel comfortable consuming the supplement.

Form

Iron supplements are available in various forms, but it’s important to choose the one that you tolerate best and best meets your needs.

Iron is naturally found in two main forms: ferrous iron and ferric iron. You may also see these two forms being referred to as “heme” and “nonheme” iron, respectively. Heme iron is found in animal foods, such as meat, poultry, and seafood. Nonheme iron is found in plant foods, like beans, grains, vegetables, and fortified foods. The body absorbs heme iron very efficiently, but only about 1% to 7% of nonheme iron is absorbed. Therefore, it is usually recommended to take a supplement in the form of ferrous, or heme, iron. While heme iron is only found in animal foods, many ferrous/heme iron supplements are 100% vegan.

One thing to note is that the amount of elemental iron varies among the different forms of iron. For example, ferrous sulfate contains only 20% elemental iron, whereas ferrous fumarate contains 33%. The supplement facts label only lists the elemental iron, so you will know exactly what you are absorbing.

Here are some of the common forms of iron used in supplements:

• Ferrous sulfate: This is an iron salt and is considered the “standard” treatment of iron deficiency, given its acceptable tolerability, high effectiveness, and low cost.
• Ferrous bisglycinate: This is known as a “chelated form.” It usually causes far fewer side effects and is just as effectively absorbed as iron sulfate. This form also might increase ferritin (the body’s storage form of iron) better. Both Barmmer and Caldwell prefer to use this form to treat iron deficiency in pregnancy in their own practices.
• Ferrous fumarate: This is an iron salt that may cause GI upset.
• Ferrous gluconate: This is an iron salt that may cause GI upset.

There are also ferric citrate and ferric sulfate, but they are absorbed less easily and need to be converted to ferrous in the body.

Iron supplements can come with some unpleasant side effects, like nausea, heartburn, pain, constipation, and diarrhea, but they can be mitigated by choosing a slow-release formulation. The product’s form of iron may still be listed as “ferrous sulfate,” but the preparation will delay the release of the iron so that it’s delivered in a more gentle way to the GI system.

Finally, you can find iron supplements as pills, liquids, or gummies, so choose the method of administration that is most comfortable to you. For some pregnant women, that might be a liquid or gummy if they feel that they are already taking numerous other prenatal supplement pills.

Ingredients and Potential Interactions

It is essential to read the ingredient list and nutrition facts panel of a supplement carefully to know which ingredients are included (and how much of each), relative to the recommended daily value of that ingredient. Please take the supplement label to a healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.

Here are some specific considerations for supplementing with iron:

Take iron supplements separately from prenatal vitamins: Again, iron is not commonly included in a prenatal vitamin, due to varying dosage needs and certain vitamin interactions. For example, “Zinc and calcium can interfere with iron absorption, even in more bioavailable forms. I always recommend spacing [out] prenatal and iron supplements,” says Barmmer.

Work with a healthcare provider if you take certain medications: According to Barmmer, “Over-the-counter medications such as antacids and acid blockers can also decrease the absorption of iron, so if someone is experiencing any heartburn or reflux, [it is ideal to work] with a healthcare practitioner.”

Take iron supplements separately from thyroid medications: Barmmer also notes that iron supplementation may interfere with thyroid medication. Pregnant women may take the drug levothyroxine (Levothroid,® Levoxyl,® Synthroid®, Tirosint,® and Unithroid®) to help maintain healthy thyroid hormone levels during pregnancy. If you take this drug and also need to be supplementing with iron, be sure to separate the two by at least four hours so that the iron does not decrease the absorption of your thyroid medication.

Take iron supplements alongside vitamin C: Taking an iron supplement with a source of vitamin C, such as orange juice, bell peppers, or a vitamin C supplement, can be a positive way to enhance iron’s absorption.

Iron Dosage

The Institute of Medicine has established a recommended daily allowance (RDA) for iron, which is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97% to 98%) healthy individuals. For pregnancy, the RDA for iron is 27 mg per day.

Note that this RDA is for non-vegetarians; if you follow a vegetarian or vegan diet, the RDA is 1.8 times higher than for meat-eaters, because heme iron from meat is better absorbed than non-heme iron found in plant-foods.

Knowing your iron status before and throughout pregnancy can best assist you in determining when to supplement and how much iron you might need to be taking. In order to determine the right dose for yourself, Barmmer says, “I always emphasize that hemoglobin and hematocrit (two markers on a standard blood test) are insufficient. Ferritin is needed, at a minimum, but running a full list of a complete [blood] panel is ideal, especially for women near the end of their pregnancy.”

Barmmer and Caldwell agree that a dose of 25 mg of elemental iron can effectively treat iron deficiency anemia in pregnancy, but be sure to speak with a healthcare professional to have a complete iron assessment and recommendations for dosing.

How Much Is Too Much?

The tolerable upper intake level (UL) established for iron in pregnancy is 45 mg. However, if you are iron deficient, a healthcare professional would recommend taking an iron supplement that is above the UL until iron levels are back to normal range.

Consuming excessive iron in pregnancy can lead to unpleasant side effects, such as constipation, nausea, abdominal pain, diarrhea, or vomiting. Long-term consumption of high doses of iron can lead to more serious gastrointestinal issues or organ damage.

Some research suggests that high iron status, as indicated by hemoglobin and/or serum ferritin, may be associated with an increased risk for low birth weight (LBW) and pre-term delivery. New research is also showing a potential link between high iron concentrations, inflammation, and gestational diabetes risk. Further research is needed.

Frequently Asked Questions

Is it safe to take an iron supplement during pregnancy?

Yes, taking an iron supplement is generally considered safe in pregnancy, and, for many pregnant women, a necessity due to the increased iron demand of the mother and fetus. As discussed, some forms of iron may cause gastrointestinal side effects that might not be pleasant or welcomed alongside other pregnancy symptoms, but they are still considered safe.

Which month of pregnancy should I start taking an iron supplement?

Iron needs vary by trimester. In the first trimester, iron needs are quite low (0.8mg/day), but they steadily increase through the second and third trimesters (3.0-7.5mg.day). Blood levels will be checked periodically throughout your pregnancy, so this will be helpful in determining when and whether you may need to start a supplement. If an iron supplement is needed, it generally may be started some time between five and seven months.

Can I meet my iron needs during pregnancy without an iron supplement?

For a non-vegetarian, it can be completely feasible to meet your iron needs for pregnancy without a supplement. Some of the best food sources of iron are: oysters, beef liver, sardines, beef, and chicken. Plant-sources of iron include fortified breakfast cereals, white beans, lentils, boiled spinach, tofu, and kidney beans. But remember that the form of iron found in these foods is less easily absorbed. Therefore, you would need to consume these foods in much greater quantities than the animal sources.

What should I look out for when considering an iron supplement for pregnancy?

When choosing an iron supplement, you will want to consider a few things: the dosage, the type of iron, and any additional ingredients in the supplement. Because people have varying iron needs, the dosage can vary from as little as 10 mg to 65 mg, so it’s important to consider how much is recommended for your personal needs before purchasing. As mentioned previously, some forms of iron are better tolerated digestively. If GI upset is something you have struggled with in pregnancy, you will want to select one that is more gentle. Finally, iron often comes as a standalone mineral supplement, but it can also be packaged with other nutrients. Some nutrients, like vitamin C, will aid in iron absorption, but other nutrients may provide much more of a vitamin or mineral than you need, especially if you’re taking them on top of a prenatal vitamin.

Why Trust Verywell Family

Casey Seiden is a registered dietitian nutritionist and certified diabetes care and education specialist based in New York City. Casey works at Maternal Fetal Medicine Associates, the premier maternal fetal medicine practice in Manhattan, where she provides nutrition therapy and counseling to women with high-risk pregnancies. She is also the founder of Casey Seiden Nutrition, a virtual private practice specializing in a non-diet approach to diabetes care and women’s health.

11 Sources

Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

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