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Anemia in Pregnancy

Also known as Iron-deficiency anemia in pregnancy, Low blood count in pregnancy. Any trimester, most common in the second and third.

Pregnancy asks your body to build far more blood, and that takes a great deal of iron, more than many people have in reserve. When it falls short, the result is anemia: blood carrying less oxygen than it should. It is one of pregnancy's most common conditions. Mild anemia is expected and easily treated, usually with iron; left unaddressed, it can leave you exhausted and, when severe, raise risks for you and your baby. This page explains why pregnancy predisposes you to it and how simple treatment restores your levels.

Know the warning signs When to call a provider
How common
About 1 in 4 or more
Iron deficiency affects roughly a quarter or more of pregnancies, and is even more common worldwide.
When
Rises through pregnancy
Most common in the second and third trimesters as iron demand climbs.
Urgency
Routine
Screened on routine bloodwork and treated with iron; severe cases need prompt care.
Outlook
Very treatable
Responds well to iron; most people recover normal levels.

Understanding it

What is anemia in pregnancy?

Anemia is a shortage of healthy red blood cells, or of the hemoglobin inside them that carries oxygen. In pregnancy it is common, and by far the most frequent kind is iron-deficiency anemia. Iron is the raw material for hemoglobin, and pregnancy sharply increases the demand.

Some drop in your blood counts is completely normal, not a disease. Your blood volume expands by around 30% to supply the placenta and baby, and the plasma rises faster than the red cells, diluting the blood and lowering hemoglobin slightly. This physiologic anemia needs no treatment. True iron-deficiency anemia is when the level falls below the thresholds set for each trimester, and that is what gets treated.

The demand is real: a pregnancy costs roughly 1,000 milligrams of iron overall, between your expanded blood supply, the placenta, and the baby. If your stores were low to start, or your diet is short on iron, they run down and anemia follows, most often in the third trimester. Folate and vitamin B12 deficiencies can cause it too, less often.

Anemia is caught on routine blood counts, often before you feel much, and is straightforward to treat. Most people do well with oral iron, an iron-rich diet, and vitamin C for absorption; when that is not enough, iron through a vein works well. The goal is healthy levels by delivery, for your energy and the blood loss of birth.

Symptoms

What are the symptoms?

Mild anemia often causes no symptoms and is found on routine bloodwork. As it deepens, it tends to bring tiredness and the classic signs of low oxygen-carrying capacity.

Early signs

  • Unusual tiredness or weakness beyond normal pregnancy fatigue
  • Dizziness or lightheadedness
  • Shortness of breath
  • Headache, trouble concentrating, or pale skin
  • A fast heartbeat
  • Craving or chewing ice, a form of pica linked to iron deficiency

Emergency signs — call 911

  • Severe or worsening shortness of breath
  • Chest pain
  • A racing or irregular heartbeat
  • Fainting

Why it matters

Risks to you and baby

Exhaustion and reduced reserve

The most immediate effect is on you: anemia deepens fatigue and leaves less reserve for the demands of pregnancy, labor, and recovery. Correcting it improves how you feel.

Less cushion for delivery blood loss

Every birth involves some blood loss. Going into delivery anemic leaves less margin and makes a postpartum hemorrhage harder to tolerate. Building them up beforehand is a key goal of treatment.

Risks when severe

More significant anemia is linked to preterm birth and low birth weight. These risks rise with severity, which is why anemia is screened for and treated rather than left to worsen.

Postpartum effects

Anemia that carries into the postpartum period can worsen fatigue and has been linked to postpartum depression. Entering birth with healthy levels helps your recovery.

How it's found

How is it diagnosed?

Anemia is diagnosed with a simple blood count, done routinely in pregnancy. If anemia is found, an iron test usually confirms iron deficiency as the cause.

Complete blood count (CBC)

Measures hemoglobin and hematocrit. Pregnancy uses trimester-specific cutoffs: below 11 in the first and third trimesters, and below 10.5 in the second, defines anemia.

Ferritin and iron studies

Ferritin reflects your iron stores. A low ferritin, generally under 30, confirms iron deficiency as the cause and guides treatment.

Additional tests when needed

If iron is not the cause, folate and vitamin B12 levels, and sometimes tests for inherited conditions like thalassemia, help identify the reason.

Screened at the first prenatal visit and again around 24 to 28 weeks, when iron demand peaks. Rechecked after starting treatment to confirm it is working.

Treatment

How is it managed?

Treatment matches the cause. For the common iron-deficiency type, oral iron plus an iron-rich diet is first-line, with iron through a vein when that is not enough.

Treatment paths

Oral iron is the mainstay: elemental iron taken daily or, increasingly, every other day, which is gentler on the stomach and absorbed just as well. Vitamin C boosts absorption; calcium, coffee, and tea reduce it. Hemoglobin is rechecked after a couple of weeks. Folate or B12 deficiency is treated by replacing that vitamin.

Medication

Oral iron supplements are first-line. When they are not tolerated or not enough, or anemia is more severe or found late, iron given intravenously restores levels effectively. A blood transfusion is reserved for severe, symptomatic anemia.

Monitoring

Blood counts are rechecked to make sure the iron is working. If hemoglobin does not rise as expected, the cause is revisited.

Can it recur?

Anemia tends to recur if iron stores are not rebuilt, and closely spaced pregnancies are a particular risk. Continuing iron for a while after birth, especially if you were anemic or lost a lot of blood, helps restore your stores.

What you can do

Can it be prevented?

  • Take your prenatal vitamin with iron

    Most prenatal vitamins contain iron, and pregnancy raises the daily need to about 27 milligrams. Taking it consistently is the simplest prevention.

  • Eat iron-rich foods

    Lean red meat, poultry, and fish provide easily absorbed iron. Beans, lentils, dark leafy greens, and iron-fortified cereals add more, especially useful in a plant-based diet.

  • Pair iron with vitamin C

    Vitamin C markedly improves absorption from supplements and plants. Have your iron with orange juice, tomatoes, or peppers, and separate it from coffee, tea, and calcium.

  • Keep your screening bloodwork

    The routine blood counts in pregnancy catch anemia early, often before symptoms, so it can be treated before it becomes significant.

Who is more at risk

Risk factors

Low iron stores at the start
Going into pregnancy with depleted iron, from heavy periods or a low-iron diet, is the biggest predictor of anemia during it.
Closely spaced pregnancies
Two pregnancies close together give iron stores little time to recover, raising the risk of anemia in the second.
Carrying multiples
A twin or higher-order pregnancy needs even more iron and blood volume, increasing the chance of anemia.
Severe morning sickness
Frequent vomiting limits how much iron and nutrition you can take in and keep down, contributing to deficiency.
A prior history of anemia
Having been anemic before, in or out of pregnancy, makes it more likely again.

Do not wait

When to call your provider or 911

  • Seek urgent care for severe or worsening shortness of breath, chest pain, a racing or irregular heartbeat, or fainting.
  • Call your provider if unusual tiredness, dizziness, or breathlessness is affecting your daily life.
  • Mention if iron supplements upset your stomach or cause constipation, so the dose or timing can be adjusted.
  • Ask about your iron levels if you are carrying multiples, had anemia before, or have closely spaced pregnancies.
  • Tell your provider if you find yourself craving or chewing ice, which can be a sign of iron deficiency.

Talking to your team

Questions to ask your provider

  • What is my hemoglobin and ferritin, and do I have iron-deficiency anemia?
  • Which iron supplement and dose do you recommend, and should I take it daily or every other day?
  • How should I take my iron to absorb it best and avoid side effects?
  • When will you recheck my levels?
  • If oral iron is not enough, would I need iron through a vein?
  • How can I build my iron back up after delivery?

Keep reading

More on anemia in pregnancy

All pregnancy guides articles

Good to Know

Anemia in Pregnancy FAQs

Common questions about anemia in pregnancy, answered.

Why is anemia so common in pregnancy?

Because your body makes about 30% more blood, and building those red cells takes a large amount of iron, roughly 1,000 milligrams over the pregnancy. If your stores cannot keep up, iron-deficiency anemia results.

What is the difference between normal pregnancy dilution and real anemia?

The plasma increases faster than the red cells, diluting the blood and lowering hemoglobin a little; this physiologic anemia needs no treatment. True anemia is when the level drops below the trimester thresholds, below 11 in the first and third and 10.5 in the second.

How is anemia treated?

Oral iron plus iron-rich foods, with vitamin C to aid absorption and levels rechecked to confirm they rise. If oral iron is not enough or not tolerated, iron through a vein works well; a transfusion is only for severe cases.

Iron pills upset my stomach. What can I do?

Common. Every-other-day dosing is often just as effective and gentler. Taking it with food, a different formulation, or a split dose can help. Do not stop it; ask your provider to adjust, and IV iron is an option if needed.

Will anemia hurt my baby?

Mild anemia usually does not, and it corrects easily. More significant anemia is linked to preterm birth and low birth weight, which is why it is screened for and treated. Raising your levels protects you both.

What foods have the most iron?

Lean red meat, poultry, and fish give the most easily absorbed iron. Beans, lentils, tofu, dark leafy greens, and fortified cereals help too. Pair plant sources with vitamin C to absorb more.

How much iron do I need in pregnancy?

About 27 milligrams a day, nearly double the pre-pregnancy amount. Most prenatal vitamins contain iron; if you develop anemia, your provider prescribes a higher therapeutic dose.

Can I prevent it?

Often, yes. A prenatal vitamin with iron, iron-rich foods with vitamin C, and keeping your screening bloodwork all help. With risk factors like heavy periods, close pregnancies, or twins, mention them so iron is watched.

Medically Reviewed · Updated

Reviewed by Dr. Grace Lin, MD, FACOG · OB-GYN

Obstetrician-gynecologist focused on reproductive and sexual health for women: pregnancy, BV, yeast, trichomoniasis and HPV/cervical screening. Our editorial guidelines →

6 Sources

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