Iron in pregnancy is essential for making hemoglobin, the protein in red blood cells that carries oxygen to other cells. During pregnancy you have almost 50 percent more blood than usual, so iron is even more important. Pregnant women need 27 milligrams of iron daily. Low iron during pregnancy can lead to anemia, so do your best to get enough iron through iron-rich foods or supplements.
Why you need iron during pregnancy
Even before you’re pregnant, your body needs iron for several reasons:
- It’s essential for making hemoglobin, the protein in red blood cells that carries oxygen to other cells.
- It’s an important component of myoglobin (a protein that helps supply oxygen to your muscles), collagen (a protein in bone, cartilage, and other connective tissue), and many enzymes.
- It helps maintain a healthy immune system.
But during pregnancy you need a lot more of this essential mineral. Here’s why:
- The amount of blood in your body increases during pregnancy until you have almost 50 percent more blood than usual. You need extra iron to make more hemoglobin.
- You need extra iron for your growing baby and placenta, especially in the second and third trimesters.
- Many women need more because they start their pregnancy with insufficient stores of iron.
- Low iron during pregnancy can lead to anemia, and severe anemia in pregnancy is associated with preterm delivery, low birth weight, and infant mortality.
How much iron do pregnant women need?
Pregnant women need significantly more iron than women who aren’t pregnant.
Pregnant women (of all ages) need: 27 milligrams (mg) of iron per day
Nonpregnant women ages 14 to 18 need: 15 mg per day
Nonpregnant women ages 19 to 50 need: 18 mg per day
Note: Breastfeeding women need 9 to 10 mg of iron per day, which is less than pregnant and nonpregnant women. This number is lower because it assumes that breastfeeding women haven’t had a period yet, so need less iron.
Iron-rich foods for pregnancy
To make sure you’re getting enough iron, eat a variety of iron-rich foods every day.
There are two forms of iron: heme and non-heme. Heme iron is found only in animal sources and is easier for your body to absorb. Non-heme iron is found in plants, iron-fortified foods, and supplements.
Red meat, poultry, and seafood contain both heme and non-heme iron and are some of the best sources of iron. But if you’re vegan or vegetarian and don’t eat animal protein, you can get iron from legumes, vegetables, and grains.
Note: Liver supplies a very high concentration of iron, but it also contains unsafe amounts of vitamin A, so it’s best to limit how much liver you eat during pregnancy.
Good sources of heme iron:
(To help visualize, 3 ounces of meat is about the size of a deck of cards.)
- 3 ounces lean beef, chuck: 2.2 mg
- 3 ounces lean beef, tenderloin: 2.0 mg
- 3 ounces roast turkey, dark meat: 2.0 mg
- 3 ounces roast turkey, breast meat: 1.4 mg
- 3 ounces roast chicken, dark meat: 1.1 mg
- 3 ounces roast chicken, breast meat: 1.1 mg
- 3 ounces light tuna, canned: 1.3 mg
- 3 ounces pork, loin chop: 1.2 mg
Good sources of non-heme iron:
- 1 cup iron-fortified ready-to-eat cereal: 24 mg
- 1 cup fortified instant oatmeal: 10 mg
- 1 cup edamame (soybeans), boiled: 8.8 mg
- 1 cup lentils, cooked: 6.6 mg
- 1 cup kidney beans, cooked: 5.2 mg
- 1 cup chickpeas: 4.8 mg
- 1 cup lima beans, cooked: 4.5 mg
- 1 cup black or pinto beans, cooked: 3.6 mg
- 1 tablespoon blackstrap molasses: 3.5 mg
- 1/2 cup firm tofu, raw: 3.4 mg
- 1/2 cup spinach, boiled: 3.2 mg
- 1 ounce pumpkin seeds, roasted: 3.2 mg
- 1 cup prune juice: 3.0 mg
- One slice whole wheat or enriched white bread: 0.9 mg
- 1/4 cup raisins: 0.75 mg
Ways to get enough iron in pregnancy
Here are some tips for getting as much iron as possible from your diet:
- Cook in a cast iron pan. Moist, acidic foods, such as tomato sauce, are especially good at soaking up iron this way.
- Include a source of vitamin C (like orange juice, strawberries, or broccoli) with every meal, especially when eating vegetarian sources of iron, like beans. Vitamin C can help you absorb up to six times more iron from your food.
- Watch out for “iron inhibitors,” which are naturally occurring substances in many healthy foods that can interfere with iron absorption. Examples of iron inhibitors include phytates in whole grains and legumes, polyphenols in coffee and tea, oxalates in soy foods and spinach, and calcium in dairy products.
If you have low iron or iron-deficiency anemia, some experts believe you shouldn’t eat iron-inhibiting foods at the same time as iron-rich foods. Others believe it’s okay to eat these foods together as long as your overall diet includes plenty of iron-rich and vitamin C-rich foods. Your provider or a dietitian can work with you to create a prenatal nutrition plan that supports healthy iron levels.
Do you need iron supplements during pregnancy?
You may. Many women start their pregnancy without enough iron to meet their body’s increased demands and are unable to bring their levels up through diet alone. But you won’t need to take additional supplements unless your provider advises you to. The iron in your prenatal vitamin will likely be all you need, unless you have (or develop) anemia.
If your provider recommends iron supplements:
- Take them one hour before or two hours after meals because iron is absorbed most easily on an empty stomach. However, you may want to take the supplement with orange juice – which is high in iron-enhancing vitamin C – to boost absorption. Don’t take your iron pill with milk, coffee, or tea because these can interfere with iron absorption.
- If your provider has recommended you take both an iron and a calcium supplement (or antacids that contain calcium), ask for advice on how to space them out during the day. Calcium also hinders iron absorption.
- Be aware that iron supplements (and the iron in your prenatal vitamins) can upset your gastrointestinal tract. The most common complaint is constipation, which is already a problem for many pregnant women. Try drinking prune juice if you’re constipated. It can help you stay regular – and it’s a good source of iron.
When taking an iron supplement, you may also have nausea or (more rarely) diarrhea. If your supplement or prenatal vitamin makes you feel queasy, try taking it with a small snack or at bedtime.
Talk to your provider if you’re experiencing unpleasant side effects from iron supplements. You may be able to prevent stomach problems by starting with a supplement that has less iron and gradually building up to the dose you need. You could also try taking the iron in smaller doses throughout the day. Your provider may suggest trying different iron supplements to find one that’s easy on your stomach. For example, some moms-to-be have fewer side effects from a timed-release iron supplement, although the trade-off is that the iron isn’t absorbed as well this way.
Finally, don’t worry if your stools look darker when you start taking iron. That’s a normal and harmless side effect.
Iron deficiency during pregnancy
When you don’t get enough iron, your stores become depleted over time. And if you no longer have enough iron to make the hemoglobin you need, you become anemic.
Iron-deficiency anemia can sap your energy and cause many other symptoms, especially if you have a severe case. It can also make it harder for your body to fight infection.
It may even impact your pregnancy: Iron-deficiency anemia – especially in early or mid-pregnancy – has been linked to a greater risk of preterm birth, having a low-birth-weight baby, and other serious complications.
If you’re anemic when you give birth, you’re more likely to need a transfusion and have other problems if you lose a lot of blood at delivery. And some research suggests an association between maternal iron deficiency and postpartum depression.
How much iron is too much?
Aim to get no more than 45 milligrams of iron a day. If you take more than that (either from an extra iron supplement or from your prenatal vitamin), it can cause your blood levels of iron to rise too high, possibly causing problems for you and your baby.