Anemia is a condition in which there is a decrease in the number of healthy red blood cells or the amount of hemoglobin circulating in the body. Anemia can affect anyone, but it is particularly common during pregnancy, when the body requires more blood cells and hemoglobin.

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The body needs to make more blood during pregnancy, so it requires more iron and vitamins to produce a protein in red blood cells called hemoglobin. This protein transports oxygen to other cells in the body.

Many pregnant people lack the necessary amount of iron during their second and third trimesters. As a result, mild anemia is common during pregnancy.

If anemia is severe during pregnancy, the developing baby may be at risk of anemia as an infant. People with anemia also have a higher risk of giving birth prematurely or delivering a low weight baby. Having anemia also increases the risk of blood loss during labor, which can make it more difficult to fight infection.

However, people can usually treat the condition by eating more iron-rich foods and taking iron supplements.

This article provides more information about anemia and the types that can occur during pregnancy. It also looks at the symptoms and risk factors and gives some prevention tips.

A person with anemia has low levels of red blood cells or hemoglobin. Hemoglobin contains iron and is the protein that gives blood its red color. It combines with oxygen from the lungs, which it transports throughout the body.

Anemia is the most common blood disease. There are more than 400 types of anemia, many of which have their own specific causes, treatments, and outlooks.

Anemia is usually an indicator of an underlying condition. An accurate diagnosis is important because anemia can lead to a reduced amount of oxygen in the body’s tissue and worsen the progression of many coexisting diseases.

Learn more about anemia.

Various types of anemia are common during pregnancy. These include:

Vitamin B12 deficiency

Vitamin B12 is essential for the body to be able to multiply red blood cells. It occurs naturally in animal products, such as eggs, meat, fish, and dairy. It is also available as a dietary supplement and a prescription medication. Fortified breakfast cereals and fortified nutritional yeasts are also good sources of vitamin B12.

Pernicious anemia is a form of anemia linked to vitamin B12 deficiency. About 15–25% of older adults with vitamin B12 deficiency have pernicious anemia.

This condition is an irreversible autoimmune disease that affects the mucous membrane of the stomach, called the gastric mucosa. It can cause gastric atrophy, a destruction of the cells in the protective stomach lining.

Pernicious anemia can also prevent the absorption of vitamin B12, even if a person is consuming adequate amounts of the vitamin. It is the most common cause of vitamin B12 deficiency worldwide.

About 151 in 100,000 people in the United States have pernicious anemia, and it is more common among females and people of European ancestry.

Learn more about vitamin B12 deficiency.

Folate deficiency anemia

During pregnancy, people require higher amounts of folate, which is a water soluble B vitamin, as folate is necessary for the development of the fetus. Folate deficiency can affect normal growth and cell division in the placenta and fetus, which can lead to birth abnormalities.

If a person does not have enough folate before and during their pregnancy, the baby may develop severe problems with the brain and spinal cord, called neural tube defects. These include spina bifida — which causes abnormalities in the nerves, spine, or both — and anencephaly, which is a fatal condition in which the fetus is missing parts of the skull and brain.

Research has also shown an association between folate deficiency and both low birth weight and preterm delivery.

Neural tube defects occur in the first few weeks of pregnancy, usually before a person knows that they are pregnant. Due to this, the Centers for Disease Control and Prevention (CDC) advise that people get 400 micrograms of folic acid daily, “in addition to consuming food with folate from a varied diet,” even if they do not plan on becoming pregnant.

Learn more about folate deficiency.

Iron deficiency anemia

A person’s iron needs increase significantly during pregnancy because iron is important for:

  • meeting the increased demands of the fetus and placenta
  • keeping up with the higher production of red blood cells
  • compensating for iron loss during the delivery of a baby

Iron deficiency anemia is the most common type of anemia among pregnant people.

Researchers estimate that more than 40% of people in the world have anemia during pregnancy. If a person does not receive treatment, iron deficiency anemia can have a significant effect on maternal and fetal health.

The research above also highlights a link between iron deficiency anemia and the following:

Learn more about iron deficiency anemia.

The symptoms of anemia during pregnancy may begin as mild and develop slowly. They can include:

  • weakness
  • fatigue
  • headaches
  • dizziness
  • pale or sallow skin
  • low body temperature
  • rapid or irregular heartbeat
  • chest pain or shortness of breath, especially with physical activity
  • brittle nails
  • pica, which refers to unusual cravings for non-food items such as paper, dirt, or sand

A person is at higher risk of becoming anemic during pregnancy if they:

  • are pregnant with more than one baby
  • have had a recent previous pregnancy
  • do not consume enough iron
  • had a heavy menstrual flow before pregnancy
  • vomit often due to morning sickness

Good nutrition is the best way to prevent anemia during pregnancy or when trying to become pregnant. Eating foods high in iron can help with maintaining the supply of iron necessary to function properly. These foods include:

  • red meat
  • dark green leafy vegetables
  • eggs
  • peanuts
  • fortified cereals

Learn more about foods rich in iron.

A doctor will likely test a person for anemia at their first prenatal visit and possibly again 4–6 weeks after delivery. If either test reveals anemia, the doctor may refer the person to a hematologist — a doctor who specializes in blood-related conditions.

An obstetrician will also prescribe vitamins to ensure that a pregnant person has enough folate and iron. If a person does develop anemia during pregnancy, they can usually treat it by taking iron supplements.

Learn more about iron supplements for anemia and pregnancy.

People require more iron as their blood levels increase during pregnancy. This increased need may result in iron deficiency and anemia.

Anemia may affect the development of the fetus, and it can cause serious health issues, including neural tube defects. These abnormalities can occur during the very early stages of pregnancy, so it is important to have enough iron and folate before becoming pregnant, as well as during and after pregnancy.

Anemia during pregnancy is often due to a deficiency in vitamin B12, folate, or iron.

In many cases, it is possible to prevent anemia during pregnancy by eating foods high in iron and taking vitamins and supplements containing iron, vitamin B12, and folate. However, a person should seek advice from a doctor or midwife before taking any new supplements.