Iron and Pregnancy

Why is it important to get enough iron?

Iron is used to make hemoglobin, a protein in red blood cells that carries oxygen to your organs and tissues. When you’re pregnant, your body makes extra blood for both you and your baby. Your body needs extra iron to make this blood and also to support your baby’s rapid growth.

If you don’t get enough iron from your diet, your body gradually depletes its iron stores, and you are at risk for becoming anemic. Iron deficiency during pregnancy is very common; the National Institutes of Health (NIH) estimates that half of all pregnant women worldwide are iron-deficient.

According to experts, iron deficiency anemia in the first two trimesters is associated with a twofold risk that your baby will be born preterm and a threefold risk of low birth weight. Fortunately, iron deficiency is easy to prevent and to treat.

Most doctors check in the first trimester and again in the third trimester to be sure that anemia has not developed. If your blood count is low, your doctor may recommend you take an iron pill in addition to a prenatal vitamin fortified with iron for the rest of your pregnancy.

How much iron do I need during pregnancy?

As soon as your pregnancy begins, your body’s iron requirement increases by 50 percent, from 18 milligrams a day to 27 mg a day. And once you give birth, you will still need additional iron; experts recommend 9 mg a day for nursing mothers. If you’re under 18 years old, you’ll need slightly more — about 10 mg.

What are the signs of iron deficiency?

When your body’s iron stores are depleted, the result is a lower than normal level of hemoglobin in your blood, a condition called anemia. You may not notice anything out of the ordinary if you’re anemic. But you may notice more obvious signs, including fatigue, breathlessness, pale skin, and brittle nails.

Should I take a supplement?

Yes. The U.S. Department of Health and Human Services recommends that all pregnant women take 27 mg a day of iron, which is considered a routine dose. However, if you have severe morning sickness and believe your iron supplement is increasing your nausea, talk to your healthcare provider. She may decrease your dosage or ask you to take the supplement in divided doses and with food. If you have an iron overload disease known as hemochromatosis, talk to your doctor, midwife, or nurse about your concerns. You’ll need to try to get sufficient iron from your diet instead.

There are three types of ferrous iron supplements: ferrous sulfate, ferrous fumarate, and ferrous gluconate. All are fine, but what’s important is the amount of elemental iron. Read the label or follow your practitioner’s instructions.

Iron is best absorbed on an empty stomach, so take it before you eat in the morning or when you go to bed at night. Certain foods and vitamins inhibit the absorption of iron. One of these is calcium, so be careful not to take your calcium at the same time as your iron supplement. If your prenatal vitamin contains calcium (which it almost certainly does), don’t take it at the same time either.

Caffeine also prevents iron absorption, so wait a while to drink tea, coffee or a caffeinated soft drink after taking your iron supplement. Better still, avoid caffeine altogether. Vitamin C, on the other hand, helps your body absorb iron, so it’s a good idea to take your iron with a glass of orange juice or other juice that is high in vitamin C. Many women find it works well to take iron in the morning with juice and then take calcium or prenatal vitamins containing calcium before bed. If, however, the iron seems to be upsetting your stomach, switch these around and take the iron before bed when you can sleep off any discomfort.

Unfortunately, taking iron supplements can cause constipation, already an annoying problem for many pregnant women. If you suffer from these unwanted side effects, try increasing the amount of fiber in your diet by eating lots of fruits and vegetables and drinking plenty of fluids.

And finally, if you already have children, be sure to keep vitamins and iron supplements out of their reach. Accidental iron poisonings are all too common among children because they can mistake the brightly colored pills for candy.

Which foods are high in iron?

The best and most easily absorbed source of iron is heme iron, the kind contained in red meat, fish and poultry. Oysters and many other types of shellfish are good sources of heme iron. However, some types of seafood contain heavy metals such as mercury, so make sure you’re not eating too much.

Nonheme iron, the kind that is less easily absorbed, is found in beans, legumes, and vegetables. This is the form of iron added to iron-enriched and iron-fortified foods. If you’re a vegetarian, you just need to eat more of these vegetables to get enough. Combining both types of iron in one meal (for example, eating chili containing both ground meat and beans) is the best way for your body to absorb the highest percent of available iron.

Sources of heme iron found in food

Chicken liver, cooked
3 ounces
12.8 mg

Oysters, breaded and fried
6 pieces
4.5 mg

Lean beef (chuck)
3 oz.
3.2 mg

Clams, breaded and fried
3/4 cup
3.0 mg

Chicken, roasted (dark meat)
3.5 oz.
1.3 mg

Chicken, roasted (white meat)
3 oz.
1.1 mg

Sources of nonheme iron

Iron-fortified cereal
3/4 cup
18 mg

Instant oatmeal (with water)
1 cup
10 mg

Lentils, boiled
1 cup
6.6 mg

Spinach, boiled
1 cup
6.4 mg

Kidney beans, boiled
1 cup
5.2 mg

Molasses (blackstrap)
1 tbsp
3.5 mg

Tofu (raw,firm)
3.4 mg

1.5 mg


American College of Obstetrics and Gynecology. Planning Your Pregnancy and Birth. Third Edition.

Center for Disease Control and Prevention. Recommendations to Prevent and Control Iron Deficiency in the United States, Mortality and Morbidity Report. 47(RR-3);1-36

National Institutes of Health. Office of Dietary Supplements, Dietary Supplement Fact Sheet: Iron.

Mayo Clinic. Iron Deficiency Anemia.

The Mayo Clinic. Morning Sickness and More: Common Problems During Pregnancy.

March of Dimes. Anemia.

Institute of Medicine, National Academy of Sciences. Dietary Reference Intakes (DRIs): Recommended Intakes for Individuals, Elements.

American Academy of Family Physicians. Anemia: When Low Iron Is the Cause.

U.S. Department of Health and Human Services. The National Women’s Health Information Center. Anemia.

March of Dimes. Caffeine in Pregnancy.

U.S. Food and Drug Administration. Preventing Iron Poisoning in Children.

Office of Dietary Supplements. Iron.

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