The 7 Best Iron Supplements for Pregnancy, According to Registered Dietitians

Fatigue is billed as just a normal part of pregnancy, but if yours is unrelenting, it might be an iron problem. Iron is an essential mineral, and maybe the unsung hero during pregnancy: You need it for hormone regulation and to support the baby’s physical and neurological growth. Iron supports hemoglobin production, an important protein in red blood cells that delivers oxygen to cells in the body. Iron needs increase during pregnancy because a pregnant person’s blood volume expands significantly in order to maintain proper circulation and to deliver sufficient oxygen to their own tissues, as well as to the placenta and baby. Low iron in pregnancy can have cognitive impacts on the baby, so being sure to address low iron in pregnancy appropriately is important for the mom and the baby.

It is estimated that iron deficiency affects one in ten pregnant women and one in four during the third trimester. Iron deficiency can increase the risk of low birth weight, premature birth, and impaired cognitive and behavioral development of the fetus. Iron supplementation can be an effective strategy to reduce the risk of iron deficiency and iron deficiency anemia during pregnancy.

To select our top iron supplements for pregnancy, our dietitians analyzed the latest research and top products on the market, evaluating dose, form, quality of ingredients, safety, and third-party testing. Our Review Board reviewed this article for medical accuracy and integrity surrounding iron supplements for pregnancy. We recommended working with your healthcare provider to assess your iron status through bloodwork to help identify your individual iron needs. 

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.

Should I Take an Iron Supplement During 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. However, if you are not meeting your iron needs through diet or your prenatal multivitamin, you may benefit from taking an iron supplement. Ayla Barmmer, MS, RD, LDN recommends getting your iron levels checked before deciding whether or not to add an iron supplement. Here are some groups who might need an iron supplement:

• Anyone who has had significant blood loss before pregnancy, including heavy menstrual periods, surgery, or frequent blood donations.
• Athletes, who often go through their iron stores faster than non-athletes.
• Those with celiac disease, inflammatory bowel disease, resections, hemorrhoids, or bariatric surgery are more at risk of iron loss, and may have trouble absorbing iron.
• People who eat a vegetarian or vegan diet, or who experience meat aversions during pregnancy

Barmmer cautions against iron supplements for those who have blood transfusions or have the condition hemochromatosis, which can lead to an over-accumulation of iron in the body. Also, 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.

Best Overall

Thorne Iron Bisglycinate

$14 at Amazon $14 at Target View on Thorne.com

Why We Recommend It

Thorne’s Iron Bisglycinate checks all of the boxes for a quality prenatal iron supplement: It's third-party tested, a well-tolerated and highly absorbable form of iron, and provides the right amount to meet many pregnancy needs. We love that Thorne’s Iron supplement utilizes a form of iron that is less likely to cause nausea or constipation. The bisglycinate form means that the iron is bound to the amino acid glycine, which helps with gentle and optimal absorption. This unique form of ferrous (iron) bisglycinate is in the form of Ferrochel, which is “ionically neutral,” meaning it does not compete with other nutrients for absorption.

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 iron deficiency in pregnancy.

This supplement is ConsumerLab.com approved and NSF Certified for Sport, so you can trust that it has been third-party tested for purity, quality, and safety. It is gluten-free, dairy-free, and soy-free, and free of artificial colorings or flavorings.

But Take Note

If you 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.

Product Details:

• Form: Capsule
• Type: Iron bisglycinate (Ferrochel)
• Dose: 25 mg
• Recommended Use: Once daily with a meal
  

Best For Preconception and Postpartum

Needed Iron for Prenatal, Pregnancy, Breastfeeding, Postpartum

$20 at Amazon View on Thisisneeded.com

Why We Recommend It

Maintaining adequate iron intake is not only important during pregnancy but also while trying to conceive and postpartum. Low iron status in the preconception phase can put you at higher risk for iron deficiency and anemia during pregnancy. Women who are vegetarian or vegan or who experience heavy or irregular menstrual cycles may be at higher risk for iron deficiency going into pregnancy. So, in those situations, it may be helpful to take an iron supplement before you get pregnant to meet the recommended intake of 18 milligrams per day pre-pregnancy. It also may be beneficial after giving birth. Even though the RDA for iron decreases from 27 milligrams during pregnancy to 9 milligrams during lactation, it can take time for your iron levels to rise after birth, 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 form and flexible dosing. One Needed iron capsule contains 13.5 mg of iron bisglycinate (as Ferrochel), the same well-tolerated and highly absorbable form of iron as our top pick. Because this is a relatively lower dose, it works well for preconception and postpartum when iron needs are lower. Of course, this supplement could work 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 (an indicator of iron status done through bloodwork).

This supplement is 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.

But Take Note

While not tested from NSF, USP, or ConsumerLab.com, Needed states their products do undergo third-party testing, but there is limited information available on their site regarding testing.  

Product Details:

• Form: Capsule
• Type: Iron bisglycinate (Ferrochel)
• Dose: 13.5 mg
• Recommended Use: One to four capsules daily, as advised by a health practitioner
  

Best Budget

CVS Health Ferrous Gluconate Iron 27 mg Tablets

$10 at CVS

Why We Recommend It

Prenatal vitamin regimens can be costly, 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 that does not skimp on quality. CVS Pharmacy supplements abide by their Tested to be Trusted standards, which require third-party testing by one of the major verification companies. This supplement is tested for purity and potency, including testing for heavy metals, pesticides, and microbial or other contaminants. It contains 27 milligrams of iron, which is the RDA for women during pregnancy. 

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.

But Take Note

The supplement contains a form of iron called ferrous gluconate, which is less bioavailable. Also, the gluconate form can be known to cause more gastrointestinal (GI) upset than other forms of iron. These tablets also contain artificial colorings. 

Product Details:

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

Best Liquid

Mary Ruth’s Prenatal and Postnatal Liquid Iron

$38 at Amazon $33 at Walmart

Why We Recommend It

If you are tired of taking prenatal vitamin pills, a liquid option may be more appealing. 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 appreciate 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, the highly absorbable and well-tolerated form found in some of our other top picks. So you can take this liquid alongside your prenatal vitamin, for example, as it will not compete for absorption with other vitamins and minerals that typically interact with iron (including calcium, zinc, and magnesium). It is recommended to take 1 tablespoon daily during pregnancy or 1 teaspoon 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.

But Take Note

Liquid supplements can be harder to measure, so make sure you are carefully dosing this supplement. Also, it contains xantham gum (a thickening and stabilizing agent), as well as the non-nutritive sweetener stevia. While both ingredients are recognized as safe by the FDA, some may choose to avoid these food additives. 

Product Details:

• Form: Liquid
• Type: Iron bisglycinate (Ferrochel)
• Dose: 27 mg
• Recommended Use: During pregnancy, take 1 tablespoon daily. During lactation, take 1 teaspoon daily. 

Best High Dose

Nature Made Iron 65 mg Tablets

$33 at Amazon $9 at Target $9 at Target

Why We Recommend It

For pregnant women diagnosed with iron deficiency or iron deficient anemia, a healthcare professional may recommend a high-dose iron supplement. We love Nature Made Iron 65 mg because it provides a high dose and comes from a trusted supplement brand. It is third-party tested, including ConsumerLab.com approval and USP certification.

The RDA for iron during pregnancy is 27 mg, but for anyone carrying twins, triplets, or quads, the need for iron increases 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. 

But Take Note

Take note this supplement contains iron in the form of ferrous sulfate, which may cause gastrointestinal discomfort for some people. To reduce discomfort, we suggest taking this supplement with a meal.

Product Details:

• 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

$21 at Amazon $19 at Target $21 at CVS

Why We Recommend It

Ferrous sulfate is a common form of iron used in supplements due to its absorbability and affordability, but it doesn’t sit well with everyone who takes it. Thankfully, Slow Fe has designed a ferrous sulfate pill that uses a controlled delivery system to minimize nausea or abdominal discomfort with iron supplements. 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, with 45 mg of iron per serving.

But Take Note

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. One of the colorants, red 40 lake, is generally considered safe to use, although research on its consumption during pregnancy is limited.

Product Details:

• Form: Tablet
• Type: Iron sulfate
• Dose: 45 mg
• Recommended Use: Take 1 tablet daily

Best Low Dose Iron

Perelel Daily Iron Ease

View on Perelelhealth.com

Why We Recommend It

If you consume some iron through your diet or prenatal vitamins but not enough to meet your needs, you may want to consider a low-dose iron supplement. We like Perelel Daily Iron Ease, with 15 milligrams of iron per serving as iron bisglycinate, the well-tolerated and highly absorbable form of supplemental iron. Developed by a team of OBGYNs (including fertility specialists), and Registered Dietitians, Perelel’s supplements are researched-backed and are also third-party tested. 

In addition to iron, it also contains vitamin C to help with iron absorption, as well as vitamin B12 and magnesium. This supplement is gluten-free, dairy and soy-free, non-GMO, and free of colorants and synthetic fillers.

But Take Note

Because this supplement contains other vitamins in minerals, make sure to check the nutrition facts on any other supplements you are taking (like a prenatal multivitamin) to make sure you are not exceeding the established Tolerable Upper Intake Levels (ULs) for any nutrients, as outlined by the NIH.

Product Details:

• Form: Iron bisglycinate 
• Type: Capsule
• Dose: 15 mg 
• Recommended Use: Take 1 capsule daily with food and water.

Our Supplement Review Process

In reviewing and researching prenatal vitamins, we consult with experts and our own in-house Registered Dietitians. 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. In order to find the best iron supplements for pregnancy, we closely consider several factors, including quality of ingredients, third-party testing certifications, and comparing different forms and dosages. For prenatal supplements especially, we prioritize products that are third-party tested for purity and potency, as the FDA does not review dietary supplements for safety and effectiveness before they go to market.

Additionally, iron supplements can vary widely in price, so we also consider a range to meet all budgets because a higher price does not necessarily equal higher quality. 

While we hope this serves as a guide, we recommend consulting with your healthcare provider before taking any supplements.

Our Experts

• McKenzie Caldwell, MPH, RD is a Registered Dietitian and the creator of the body-positive fertility and prenatal nutrition program Fully Nourished Pregnancy.
• Ayla Barmmer, MS, RD, LDN is a Registered Dietitian and founder and CEO of FullWell, and owner of Boston Functional Nutrition.
• Anne Cook Carroll, MS, RD, CDN is a Registered Dietitian who works with patients, including pre and post-natal women, to meet their health goals. She educates patients on the appropriate usage of supplements to optimize their nutritional status and overall health. She also specializes in supplement research and analysis.

Iron Supplement Dosage & Safety

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 pregnant women, the RDA for iron is 27 milligrams 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. For women who are lactating, the RDA is 9 milligrams per day. For women between the ages of 19 and 50 who are not pregnant or lactating, the RDA is 18 milligrams per day.

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 take. 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 individual dosing.

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 during 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 and other health complications.

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 tea, coffee, and prenatal vitamins: Some forms of supplemental iron can compete for absorption with other nutrients. For example, “Zinc and calcium can interfere with iron absorption, even in some of the more bioavailable forms. I always recommend spacing [out] prenatal and iron supplements,” says Barmmer.

Tea and coffee can also interfere with iron absorption and should be spaced out from taking an iron supplement.

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 further enhance iron absorption.

Types of Iron Supplements

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. 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 and is less bioavailable compared to other forms of supplemental iron.

There are also ferric citrate and ferric sulfate forms, but they are not absorbed as easily as other forms of iron. In addition, this form needs to be converted to the ferrous form 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 powders, so choose the method of administration that is most comfortable for 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.

Note those with severe anemia in pregnancy will often be offered IV infusions of iron rather than oral supplementation because an IV is more effective and does not cause constipation.

Who We Are

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.