Iron: It’s a must-have nutrient, especially during pregnancy. Not only does the essential mineral help keep you energized (which, if you’ve ever been pregnant, you know how tiring it can be), but it also helps support a fetus’s growth and development through each trimester. This is why finding the best iron supplement for pregnancy is crucial.

But how exactly does the mineral work in the body? “Iron helps the body produce hemoglobin, the protein in red blood cells that carry oxygen,” Prati Sharma, MD, board-certified OB/GYN, reproductive endocrinologist, and medical advisor for Bird&Be fertility brand, tells Well+Good. In pregnancy, Dr. Sharma says getting enough iron is non-negotiable since depleted levels may up your risk for issues like preeclampsia¹ (high blood pressure), hypothyroidism (underactive thyroid), pre-term birth², and stunted growth³.

With so many iron supplement options on the market, finding a safe and effective product can feel overwhelming. The good news? Prenatal experts agree that there are a few key features to look for when purchasing an iron supplement.

Below, we’ve compiled everything you need to know, plus eight of our favorite iron supplement picks.

Best iron supplements for pregnancy, at a glance

Fullwell Fertility Iron Bump, $20Bird&Be The Gentle Prenatal, $32NaturesPlus HEMA-PLEX Slow-Release Tablets, $14Needed Prenatal Iron, $21Life Extension Iron Protein Plus, $18NOW Foods Iron Liquid, $20MegaFood Iron Energy Gummies, $20Thorne Ferrasorb, $24

What to look for in an iron supplement for pregnancy

“When choosing an iron supplement for pregnancy, there are several factors to consider to ensure optimal effectiveness and safety,” Lauren Manaker, MS, RDN, registered dietitian nutritionist and author of The First Time Mom’s Pregnancy Cookbook, tells Well+Good. Here’s a breakdown of the key features to look for:

1. Iron dose

Most pregnant people need at least 27 milligrams of iron per day during pregnancy. While your prenatal multivitamin typically covers this, some people with a pre-existing iron deficiency may need additional iron on top of their prenatal. Manaker says that each person’s iron needs may vary, so it’s important to consult a healthcare provider who can assess your iron levels and provide personalized recommendations.

2. Iron form

“Opt for a supplement that contains a highly absorbable form of iron, such as ferrous bisglycinate⁴ or ferrous fumarate,” says Manaker. She adds that these forms of iron are generally well-tolerated (meaning, they could be easier on your stomach) and have higher absorption rates than other forms of iron, i.e., more of it gets into your bloodstream.

3. Third-party testing

Most dietary supplements aren’t regulated by the Food and Drug Administration (FDA), so Manaker recommends choosing a supplement that has been third-party tested for quality, purity, and accuracy of the stated ingredients to make sure you’re getting a reliable and trustworthy product. Some third-party certifications that help ensure a product meets rigorous quality standards include the National Sanitation Foundation (NSF) International and the United States Pharmacopeia (USP).

4. Other beneficial ingredients

“Consider supplements that also contain other essential nutrients for pregnancy,” advises Manaker, “such as vitamin C, which may enhance iron absorption.”

Iron supplements can cause constipation

Another important thing to keep in mind when searching for an iron supplement is that some kinds can lead to backed-up bowels. “Higher doses can be hard to tolerate, with constipation being the most common side effect,” says Parti Sharma, MD, a board-certified OB/GYN, reproductive endocrinologist, and medical advisor for Bird&Be fertility brand.

If opting for more gentle forms (like ferrous bisglycinate chelate) doesn’t help, Jillian LoPiano, MD, an OB/GYN and chief health officer at Wisp recommends taking a stool softener (such as docusate or Miralax), which is safe and often prescribed during pregnancy. Just be sure to talk with your healthcare provider before trying it.

Without further ado, here are our top picks.

The 8 best iron supplements to take during pregnancy

Best Overall: Fullwell Fertility Iron Bump — $20.00

Dosage: 1 capsule

Iron per serving: 25 milligrams

Type of iron: Ferrous bisglycinate

Emily Harland, RDN, LDN, a registered dietitian nutritionist with Worley Nutrition Group recommends these iron capsules from Fullwell Fertility because they’re easily absorbed, gentle on your digestive tract (some iron pills can increase your risk of constipation), and are third-party tested for contaminants, heavy metals, and for quality assurance. “I recommend it to all of my clients needing a high-quality iron supplement,” Harland adds.

Pros:

• Contains vitamin C to help absorption
• Gentle on the stomach
• Third-party tested
• Free from most common allergens, including gluten, wheat, dairy, peanuts, tree nuts, and shellfish

Cons:

• Contains a proprietary blend of veggie powders and botanical extracts, which some people may not need

Best for Sensitive Stomachs: Bird&Be The Gentle Prenatal — $32.00

Dosage: 3 pills

Iron per serving: 27 milligrams

Type of iron: Ferrous bisglycinate chelate

Dr. Sharma loves this product because it’s a prenatal vitamin with iron separated into its own capsules. “If the pregnant person is really sick, they can split up the capsules throughout the day and take the iron with whatever food they’re able to keep down,” she says.

She adds that many of her patients are able to tolerate these pills, even when sick, because the type of iron used (ferrous bisglycinate chelate) helps to prevent an upset stomach and constipation.

Pros:

• Vegan-friendly
• Free from most allergens, including gluten, dairy, yeast, artificial colors and dyes, and preservatives
• GMP-certified
• Third-party tested
• Formulated by fertility doctors

Cons:

• One serving size is three pills
• Pricey

Best Non-Constipating: HEMA-PLEX Slow Release by NaturesPlus — $15.00

Dosage: 1 tablet

Iron per serving: 85 milligrams

Type of iron: Amino acid chelate/complex

If iron pills tend to give you constipation even when you’re not pregnant, this product from Nature’s Plus might do the trick. “This high-potency, time-released formula pairs plant-based iron with vitamin C and copper, offering the perfect solution for pregnant people experiencing anemia—sans unwanted side effects [like constipation],” says Brooke Miner, MS, RDN, LDN, a registered dietitian nutritionist at Sunshine State Dietitian in Florida.

Miner adds that all products by this brand are USDA organic and NSF-certified, giving peace of mind to those who consume them.

Pros:

• Contains vitamin C to boost iron absorption
• Slow-release to maximize absorption
• Gentle on the stomach
• Third-party tested

Cons:

• The dose may too high for some people

Best Vegan: Needed Prenatal Iron — $21.00

Dosage: 1 capsule

Iron per serving: 13.5 milligrams

Type of iron: Ferrochel (ferrous bisglycinate)

Registered dietitian nutritionist Megan Scutti, RDN, LDN recommends Needed iron because it’s vegan, non-GMO, free from the top nine food allergens and gluten, and doesn’t contain any unwanted fillers. Not only are the capsules easy to swallow, but their low iron content per serving allows you to personalize your dose depending on your stage of pregnancy, recommended iron levels, and dietary lifestyle. “This makes it the perfect supplement no matter your dietary needs,” Scutti adds.

Pros;

• Vegan-friendly
• Non-GMO
• Free from top nine food allergens and gluten
• No unwanted fillers
• Third-party tested

Cons:

• Pricey

Best Absorbing: Life Extension Iron Protein Plus — $18.00

Dosage: 1 capsule

Iron per serving: 15 milligrams

Type of iron: IronAid (iron protein succinylate)

Manaker recommends this pick from Life Extension because it’s highly absorbable compared to some other types. Why is that? It’s made with a form of iron called iron protein succinylate, which “consists of an iron bound with a protein to help improve its absorption in the digestive system,” Manaker adds. The only downside is that the iron per serving is pretty low, so you might have to take more than one capsule if you are deficient.

Pros:

• Affordable
• Highly absorbable form of iron
• Third-party tested
• Non-GMO
• Vegetarian friendly

Cons:

• The iron dose may be too low for people with severe deficiency

Best Liquid: NOW Foods Iron Liquid — $20.00

Dosage: 2 teaspoons

Iron per serving: 18 milligrams

Type of iron: Ferric glycinate

When it comes to the best liquid iron supplement for pregnancy, Manaker turns to NOW Foods Liquid Iron because it provides 18 milligrams of iron per serving. Plus, “this supplement is made with iron in the ferric glycinate form, which is a taste-free, well-absorbed form of iron,” she adds. It’s also dairy-, gluten-, and sugar-free, non-GMO, and Kosher, making it a good choice for a variety of dietary needs.

Pros:

• Highly absorbable form of iron
• Flavorless
• Non-constipating
• Third-party tested

Cons:

• Often out of stock on NOW Foods website
• Pricey

Best Gummy: MegaFood Iron Energy Gummies — $18.00

Dosage: 1 gummy, three times daily

Iron per serving: 4 milligrams (for one gummy)

Type of iron: Iron bisglycinate

If swallowing a pill or drinking a (interestingly flavored) liquid is not your jam, a gummy might help you get the daily iron you need. Manaker says this pick from MegaFood has only one gram of added sugar per gummy, and includes key ingredients like iron bisgylcinate, vitamin B12, and vitamin B6. “They’re also free from gelatin, so vegetarians can enjoy them,” she adds. “And like all MegaFood products, these are tested for over 150 pesticides.”

An added bonus? They come in a delicious strawberry flavor and are easy on the stomach.

Editor’s note: Manaker is on MegaFood’s Nutrition Collaborative team.

Pros:

• Vegetarian-friendly
• Easy on the stomach
• Third-party tested

Cons:

• Low dose of iron

Best with Vitamin C: Thorne Ferrasorb — $22.00

Dosage: 1 capsule, one to three times daily

Iron per serving: 36 milligrams

Type of iron: Ferrochel (ferrous bisglycinate chelate)

Taking iron supplements with a source of vitamin C can help the nutrient better absorb into your stomach and eventually your bloodstream. But instead of having to drink a glass of orange juice or take a separate vitamin C tablet, Thorne Ferrasorb comes with both iron and vitamin C for your convenience.

The specific type of iron in this pill is ferrous bisgylcinate, which may be easier on the stomach, plus “it contains ingredients like folate and B12, to help reduce the risk of deficiencies of other B vitamins,” says Manaker. This makes it a great choice for preventing anemia during pregnancy, as vitamin B deficiency can also lead to anemia.

Just keep in mind: If you’re already taking a prenatal multivitamin with B-complex, talk to your healthcare provider before adding Thorne Ferrasorb, as you could end up over-supplementing.

Pros:

• Contains vitamin C to improve iron absorption
• Contains other B vitamins
• Gluten-, soy-, and dairy-free
• Third-party tested by NSF

Cons:

• Risk of B vitamin over-supplementation if also taking a prenatal vitamin

The final takeaway

Finding the best iron supplement while you’re pregnant can be difficult, but with the help of your healthcare provider—who can test your iron levels and provide recommendations—you can help prevent iron and nutrient deficiencies that may increase your risk of pregnancy complications. If you’re ever unsure of a product or supplement’s safety and efficacy, reach out to your provider for guidance.