The Importance of Iron in Pregnancy: What Women Should Know
Getting enough iron in your diet might not be the first thing on your mind when you learn you’re pregnant, but this mineral is essential for a healthy pregnancy. Women of reproductive age naturally lose iron monthly during menstruation, so many enter pregnancy with low iron levels. As pregnancy progresses, the body’s need for iron increases even more.
Iron deficiency is common in pregnancy, affecting approximately 15% to 20% of women, and it becomes more widespread as pregnancy advances. According to one recent study, 84% of pregnant women experience iron deficiency during their third trimester. Iron deficiency can lead to anemia, a more serious condition that can cause heart issues and complications during pregnancy and postpartum.
“Iron deficiency anemia is associated with serious adverse outcomes including low birth weight, preterm birth, postpartum hemorrhage, stillbirth, neonatal death, and growth problems,” says Tulin Ozcan, MD, a Yale Medicine maternal–fetal medicine specialist. “Plus, the rapidly developing brain is at particular risk of iron deficiency, and neurocognitive impairment can occur.”
Fortunately, there are proven ways to prevent iron deficiency and iron deficiency anemia in pregnancy. One key recommendation from the Centers for Disease Control and Prevention is universal iron supplementation for pregnant women.
“The typical American diet, along with a woman’s own iron reserves, are insufficient sources for the increased iron requirements during pregnancy,” Dr. Ozcan explains. “The typical diet contains 15 milligrams of elemental iron per day while the recommended daily dietary allowances should be 27 milligrams. Therefore, routine iron supplementation is recommended using prenatal vitamins for all pregnant women.”
To monitor iron levels, doctors screen for deficiencies throughout pregnancy—typically at the first prenatal appointment and then again between weeks 24 and 28.
What’s the difference between iron deficiency and anemia?
It can be confusing to distinguish between iron deficiency and iron deficiency anemia. Iron deficiency is the depletion of total-body iron. In other words, the body has dipped below its ideal iron levels, but it may be hard to notice symptoms, which can include fatigue, difficulty focusing, and hair and nail changes.
In contrast, iron deficiency anemia occurs when the shortage becomes significant enough to reduce the production of healthy red blood cells and hemoglobin. As a result, the body cannot effectively deliver enough oxygen to its cells, tissues, and organs.
Iron deficiency anemia is considered the “end stage” of the iron deficiency process and is the leading cause of anemia. Common symptoms include extreme fatigue and weakness, pale skin, shortness of breath, headaches and dizziness, chest pain and rapid heartbeat, and cold hands and feet.
The main causes of iron deficiency and anemia are low dietary iron intake and insufficient iron absorption. These are increased during periods of life when iron requirements are particularly high, such as rapid growth in infants, preschool children and adolescents, as well as during the reproductive years in women, especially during pregnancy and postpartum.
“Iron is a crucial component of hemoglobin, a protein found in red blood cells that carries oxygen from the lungs to the rest of the body,” Dr. Ozcan explains. “It is also a part of many essential non-hemoglobin proteins that are involved in DNA replication and repair, energy production, and immune response.”
How is iron deficiency detected?
To assess iron stores, doctors typically measure a protein in the blood called ferritin, which is considered the best marker for iron deficiency. However, some health experts disagree on the exact definition of iron deficiency.
While the World Health Organization sets the threshold for low iron at 15 micrograms per liter of ferritin, some argue this cutoff is too low. In the United States, routine screening for low ferritin is not always part of adult checkups, though it is standard during pregnancy.
George Goshua, MD, MSc, a Yale Medicine hematologist–oncologist, recently published research on the benefits and costs of screening adult women for iron deficiency in the American Journal of Hematology, concluding that adjusting the diagnostic bar for iron deficiency upward to 25 micrograms per liter of ferritin and introducing routine screening for women of reproductive age could be a highly cost-effective public health policy.
How much iron does a pregnant woman need?
During pregnancy, additional iron is needed to support the growing fetus, maternal needs, and to compensate for blood loss during delivery. While experts may disagree on the exact cutoff for ferritin levels during pregnancy, clinicians generally consider levels below 30 micrograms per liter as indicative of iron deficiency in pregnancy.
How is iron deficiency treated in pregnancy?
All pregnant women are advised to take a prenatal vitamin that includes iron. If ferritin levels are low and other blood tests point to iron deficiency anemia, doctors recommend an additional oral iron supplement in the form of pills or liquid.
Research suggests that taking an iron supplement every other day is just as effective as taking it every day—and may be gentler on the digestive system.
If iron supplementation is not tolerated or is ineffective, a doctor may recommend an iron infusion delivered intravenously.
Taking action to maintain healthy iron levels during pregnancy is vital for both mother and baby. If you have concerns about fatigue, weakness, or any symptoms of low iron, be sure to discuss them with your health care provider.
