Iron-Deficiency Anaemia in Pregnancy: Symptoms, Tests and Treatment
Key message: Iron needs rise in pregnancy. Anaemia can cause fatigue, breathlessness and palpitations and reduces the body's…
Key message: Iron needs rise in pregnancy. Anaemia can cause fatigue, breathlessness and palpitations and reduces the body’s reserve for birth, but it is usually treatable with the right diagnosis, iron plan and follow-up.
Get urgent help: Seek urgent care for chest pain, severe breathlessness at rest, fainting, a very fast heartbeat with weakness, heavy bleeding, black tarry stools or vomiting blood. Do not assume severe symptoms are only anaemia.
What symptoms can occur?
Mild anaemia may cause no clear symptoms, so routine blood testing matters.
- Unusual or worsening fatigue and weakness.
- Breathlessness on mild activity.
- Palpitations, dizziness or headaches.
- Pale skin or poor concentration.
- Restless legs or unusual cravings such as ice in some patients.
Which tests are used?
Pregnancy-specific haemoglobin thresholds and local laboratory ranges are used. Not all anaemia is caused by iron deficiency.
- Full blood count, including haemoglobin and red-cell indices.
- Ferritin when iron deficiency needs confirmation or response is unclear.
- Tests for folate, vitamin B12, haemoglobin disorders, bleeding or another cause when indicated.
- Repeat blood count after treatment to confirm improvement.
Why does treatment matter?
Untreated significant anaemia can worsen fatigue and breathlessness and leaves less reserve if bleeding occurs at birth. Severe anaemia may be associated with preterm birth or low birth weight, although risk depends on the cause and severity.
Treatment should start early enough to improve levels before delivery.
How is oral iron taken?
- Use the preparation and elemental-iron dose prescribed by the clinical team.
- Take it at the time of day and frequency advised; alternate-day dosing may be used in selected plans.
- Vitamin C-containing food or drink may improve absorption.
- Tea, coffee, calcium, antacids and some medicines can reduce absorption and may need separation.
- Keep iron out of children’s reach because overdose is dangerous.
How are side effects managed?
Nausea, abdominal discomfort, constipation and dark stools are common. Do not stop silently: a different preparation, lower frequency, timing change or constipation plan may help.
Dark stool is expected, but black tarry sticky stool with illness or bleeding symptoms needs assessment.
When is intravenous iron considered?
IV iron is given in a monitored setting because reactions are uncommon but possible. It is not identical to a blood transfusion.
- Oral iron is not tolerated or does not work despite correct use.
- Anaemia is moderate or severe and delivery is approaching.
- Absorption is poor or ongoing blood loss continues.
- A faster response is clinically important.
When is transfusion used?
Blood transfusion is reserved for selected severe or symptomatic cases, active bleeding or urgent situations. The decision considers symptoms, haemoglobin, gestation and expected blood loss—not one number alone.
Iron treatment is still needed when iron deficiency remains.
Which foods contain iron?
- Meat and poultry, with pregnancy-safe food handling.
- Beans, lentils, chickpeas and fortified cereals.
- Dark-green vegetables, nuts and seeds.
- Combining plant iron with vitamin C.
- Avoiding liver and high-retinol products in pregnancy despite their iron content.
How is birth and postnatal care planned?
Recheck the blood count, treat the cause and plan place of birth according to severity and bleeding risk. Continue treatment for the recommended period after haemoglobin improves to restore iron stores.
Postpartum bleeding, persistent symptoms or poor response needs reassessment.
Frequently asked questions
Are dark stools from iron normal?
Yes, but black tarry stool with illness or bleeding symptoms needs urgent review.
Can I stop iron when haemoglobin becomes normal?
Usually treatment continues for a period to refill iron stores; follow the plan.
Does iron always cause constipation?
Not always, and preparation or dosing changes can help.
Is IV iron a blood transfusion?
No. It provides iron through a vein; blood transfusion contains donor red cells.
Can food alone treat significant anaemia?
Diet supports treatment but often cannot replace prescribed iron when deficiency is established.
Your next step
Bring blood-count and ferritin results, current iron dose and side effects to review. Severe breathlessness, fainting or bleeding needs urgent assessment.
Medical and content review: Dr Mohamed Abdelghany, Obstetrics & Gynecology Specialist, MRCOG (UK), MSc Obstetrics & Gynecology – Kasr Al-Ainy, Cairo University.
Last reviewed: 23 August 2026.
This information is for general education and does not replace individual medical assessment. Severe, sudden or concerning symptoms should not wait for a routine appointment.
