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.
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. 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 art time of publication: $13 ($0.22 per serving) 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) 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) 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) 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) 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) 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) 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.
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:
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.
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. 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.
