Beyond the Prenatal: Do You Need An Iron Supplement During Pregnancy?

The amount of blood in your body increases by up to 50% when you’re pregnant. This helps ensure that enough blood and nutrients can reach your growing baby. One nutrient that’s especially important during pregnancy is iron. Getting too little iron during pregnancy can lead to iron-deficiency anemia (low red blood cell levels). This can put your baby at risk of preterm delivery and low birth weight.

For this reason, iron is typically included in most prenatal vitamins. But should you take an additional iron supplement during pregnancy? Here’s what you should know.

How much iron do you need during pregnancy?

Iron is an essential mineral for everyone. It helps your body make hemoglobin (a protein in your red blood cells). Hemoglobin helps your blood carry oxygen from the lungs to the rest of the body. Iron also helps your body make myoglobin, a protein that helps deliver oxygen to your muscles.

During pregnancy, you need more iron than usual. Adult women who aren’t pregnant need 18 mg of iron daily. But pregnant women need 27 mg daily.

There are three main reasons you need more iron during pregnancy:

1. You have a larger amount of blood in your body during pregnancy. More blood means more red blood cells. And red blood cells need iron to do their job.

2. Your baby needs iron. During pregnancy, you have a growing baby that also has iron needs. In fact, your baby will store iron to use in the first six months after birth.

3. The placenta has iron needs, too. The placenta is an organ that develops during pregnancy. During pregnancy, the placenta stores iron to protect the baby in case the mother has a low iron supply.

Do you need an iron supplement during pregnancy?

Not necessarily. It’s generally recommended that all pregnant women in the U.S. eat an iron-rich diet and take a daily prenatal vitamin with iron. But if your prenatal vitamin doesn’t contain iron, or if your iron levels are low, you may need an additional iron supplement.

But experts don’t always agree on the specifics of supplementing iron during pregnancy. A few organizations have differing views:

• American College of Obstetricians and Gynecologists (ACOG): ACOG recommends taking a prenatal vitamin with iron during pregnancy. Along with a healthy diet, this may be enough to meet your iron needs. ACOG doesn’t specify how much iron should be in your prenatal vitamin.

• World Health Organization (WHO): WHO recommends a daily iron supplement of 30 mg to 60 mg. This could be part of your prenatal vitamin or through a separate iron supplement.

• U.S. Preventive Services Task Force (USPSTF): USPSTF states there’s not enough research to recommend iron supplements for all pregnant women. They believe that studies are conflicting on whether all pregnant women — including those with normal iron levels — need additional iron.

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Despite a lack of clear guidelines, your prenatal care team will likely recommend a daily prenatal vitamin with iron and an iron-rich diet. They’ll also likely run blood tests to check your iron levels during pregnancy. If you’re at risk for iron-deficiency anemia, they may recommend adding an iron supplement in addition to your prenatal vitamin with iron.

You shouldn’t take extra iron on your own or double up on your prenatal vitamin to try and raise your iron levels. Too much iron can be harmful (more on that later). If you have concerns about your iron levels during pregnancy, reach out to your prenatal care team for guidance.

Best food sources of iron during pregnancy

Iron comes in two forms: heme iron and non-heme iron. Heme iron is more easily absorbed by the body. It’s found in animal sources, such as meat, seafood, and poultry.

Plant-based foods and iron-fortified foods have non-heme iron, which is harder for your body to absorb. But adding foods with vitamin C (such as citrus fruits, tomatoes, and broccoli) to your diet can help you absorb non-heme iron.

Some animal sources with the highest amount of iron include:

• Oysters: 8 mg in 3 oz

• Beef: 2 mg in 3 oz

• Canned sardines: 2 mg in 3 oz

• Chicken: 1 mg in 3 oz

Some of the best plant-based sources of iron include:

• Fortified whole wheat cereal: 18 mg in ¾ cup

• Canned white beans: 8 mg in 1 cup

• Boiled spinach: 3 mg in ½ cup

• Tofu: 3 mg in ½ cup

Eating a balanced diet can help ensure you get enough iron. Many foods, such as bread and cereals, have iron added to them to help ensure it’s part of your daily diet. Checking your food labels and keeping a daily food journal can help you track how much iron you’re consuming.

Best iron supplements during pregnancy

If your prenatal care team recommends an iron supplement, there are many types of over-the-counter (OTC) supplements to choose from. Examples include:

• Ferrous gluconate

• Ferrous fumarate

• Ferrous sulfate

• Ferrous bisglycinate

• Ferric citrate

Iron supplements are similarly effective. But you may prefer one product over another for various reasons. For example, ferrous bisglycinate has been found to have fewer side effects than ferrous fumarate. Or maybe you prefer a supplement that’s vegan or one that comes in a liquid or chewable form. Cost may also be a factor.

Regardless of which supplement you choose, pay attention to the amount of “elemental iron” in the product when it comes to the dosage. Elemental iron refers to the amount of iron your body can absorb. It’s usually the smaller number on the iron product’s label. For example, a ferrous sulfate 325 mg tablet contains 65 mg of elemental iron.

It’s best to take an iron supplement on an empty stomach. And you may also need to separate it from your other medications. Your prenatal care team can help you find the right form and dosage of iron for your needs. As mentioned, don’t take an iron supplement on your own without the guidance of a healthcare professional.

Do iron supplements interact with any medications?

Yes, iron supplements can interact with certain medications as well as certain foods. You should avoid taking an iron supplement within 2 hours of thyroid hormone medications, some antibiotics, and certain heartburn medications. You should also avoid dairy products and coffee or tea within 2 hours of taking iron — they can prevent your body from absorbing it properly. Orange juice is a better option, as it can help with iron absorption.

Why is low iron in pregnancy dangerous?

Low iron levels can have negative effects for the mother if left untreated, such as:

• Preeclampsia

• Higher risk of infection

• Heart problems, including arrhythmias or heart failure

Your growing baby may also have complications as a result of not getting enough iron. Some studies have shown that babies who don’t get enough iron are more likely to be born premature or at a low birth weight.

What are symptoms of low iron during pregnancy?

You may not always feel symptoms of low iron levels, especially at first. But once anemia develops, you may notice symptoms including:

• Shortness of breath

• Tiredness

• Weakness

• Hair loss

• Leg cramping

Some symptoms of low iron can mimic symptoms of pregnancy itself. However, if you have any ongoing symptoms of iron-deficiency anemia, talk to your prenatal care team.

Is there such a thing as too much iron in pregnancy?

Yes, too much iron can be harmful. So you shouldn’t take extra iron during pregnancy without guidance from a healthcare professional.

In general, excess iron intake can cause stomach issues, including vomiting and ulcers. Very high doses can lead to organ failure and even death in severe cases. Specifically during pregnancy, excess iron may raise the risk of eclampsia in the mother. It may also lead to growth and development problems for the infant, both before and after birth.

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Written by:

Rachel Feaster, PharmD, BCOP, BCPS

Rachel Feaster has over 10 years of professional experience in ambulatory, inpatient, pharmacogenomics, and oncology care. She is board certified in oncology and pharmacotherapy.

Edited by:

Stacia Woodcock, PharmD

Stacia Woodcock, PharmD, is a pharmacy editor for GoodRx. She earned her Doctor of Pharmacy degree from the University of Kentucky and is licensed in New York and Massachusetts.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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