Anaemia During Pregnancy: Symptoms, Risks and Treatment
Table of Contents
Key takeaways
- Anaemia in pregnancy means the blood has too little haemoglobin or too few healthy red blood cells to carry oxygen as well as it should.
- Iron deficiency is common in pregnancy because blood volume expands and the baby, placenta and mother’s body all need iron.
- Symptoms such as extreme tiredness, breathlessness, palpitations, dizziness, headaches, pale skin, restless legs or craving ice should be discussed with a midwife or GP.
- Treatment may include prescribed iron tablets, dietary changes, B12 or folate replacement, intravenous iron, or rarely transfusion if anaemia is severe.
- Seek urgent maternity advice for severe breathlessness, chest pain, fainting, heavy bleeding, reduced fetal movements or symptoms that feel suddenly worse.
Overview
Anaemia during pregnancy is common, but it should not be brushed off as “just pregnancy tiredness”. Anaemia means there is not enough haemoglobin or healthy red blood cells to carry oxygen around the body effectively. Haemoglobin is the iron-containing protein in red blood cells that delivers oxygen to the mother’s organs and the developing baby.
Pregnancy increases demand on the blood system. Plasma volume rises, red blood cell production increases, and iron is needed for the placenta and baby as well as for the mother. If iron stores are low before pregnancy, or intake and absorption do not keep up, iron deficiency anaemia can develop.
Iron deficiency is the most common cause, but it is not the only one. Vitamin B12 or folate deficiency, inherited haemoglobin conditions, chronic inflammation, kidney disease, bleeding, gut absorption problems or previous bariatric surgery can also contribute. The right treatment depends on the cause, so blood tests and follow-up matter.
Pregnant women should be supported to make informed decisions about tests and treatment. If symptoms feel significant, or if previous anaemia has happened in pregnancy, it is reasonable to raise this early with a midwife, GP or obstetric team.
Symptoms
Some symptoms of anaemia overlap with ordinary pregnancy changes, which can make it hard to spot. The difference is often the intensity, persistence or combination of symptoms.
Possible symptoms include:
- extreme tiredness that is not relieved by rest
- weakness or feeling unusually wiped out after normal activity
- shortness of breath, especially on stairs or mild exertion
- palpitations or a racing heartbeat
- dizziness, light-headedness or faintness
- headaches
- paler skin, gums or inner eyelids than usual
- cold hands and feet
- restless legs or poor sleep
- sore tongue, mouth ulcers or cracks at the corners of the mouth
- hair shedding or brittle nails
- craving non-food items such as ice, paper or clay, known as pica
- pins and needles, memory problems or visual symptoms, which may suggest B12 deficiency
Symptoms alone cannot confirm anaemia. A full blood count and, often, iron or vitamin tests are needed. Do not assume that every pregnancy symptom is due to anaemia, especially if breathlessness, chest pain, fainting or headache is severe.
Why anaemia happens in pregnancy
During pregnancy, the body needs more iron to make extra haemoglobin. If iron stores are low, red blood cells may become smaller and carry less oxygen. This can happen even with a reasonable diet because pregnancy demand is high.
Risk factors include:
- heavy periods before pregnancy
- anaemia or low ferritin before conception
- pregnancies close together
- multiple pregnancy, such as twins or triplets
- severe nausea and vomiting affecting food intake
- vegetarian or vegan diet without reliable B12 planning
- coeliac disease, inflammatory bowel disease or previous stomach or bowel surgery
- previous postpartum haemorrhage or current bleeding in pregnancy
- teenage pregnancy or limited access to nutritious food
- inherited blood conditions such as sickle cell disease or thalassaemia
Folate is also important because it helps the body make red blood cells and supports fetal neural tube development early in pregnancy. Vitamin B12 is needed for red blood cell production and nervous system health. B12 deficiency can occur in people with pernicious anaemia, low animal-product intake, absorption problems or some medicine effects.
Possible risks for mother and baby
Mild anaemia is common and treatable, but untreated or severe anaemia can increase strain on the body. The heart may have to pump harder to deliver enough oxygen, which can worsen palpitations, breathlessness and exhaustion.
Possible complications include reduced ability to cope with blood loss at birth, increased need for treatment after delivery, greater tiredness in the postnatal period and, in more severe cases, heart or lung strain. In pregnancy, folate deficiency is also linked with pregnancy complications and birth defects, which is why folic acid supplementation is routinely recommended before and in early pregnancy.
For the baby, anaemia may be linked with growth concerns, premature birth or low birth weight depending on severity, timing and cause. This does not mean every person with anaemia will have complications. It means diagnosis, treatment and monitoring are worth taking seriously.
Blood tests and diagnosis
NICE antenatal guidance recommends offering a full blood count at the first face-to-face antenatal appointment and again at the 28-week appointment. A full blood count checks haemoglobin, red blood cell size and other blood cells.
If anaemia is found, the maternity team may request ferritin or iron studies to assess iron stores. B12, folate, kidney, liver, thyroid, inflammation or haemoglobinopathy tests may be considered depending on the person’s background, symptoms and blood count pattern.
Screening for sickle cell and thalassaemia is also part of antenatal care in the UK. These inherited conditions are not the same as iron deficiency and need different counselling and management. Taking iron without confirmation may not be appropriate for every anaemia pattern.
Tell the midwife or doctor about previous anaemia, heavy periods, bowel symptoms, bleeding, dietary restrictions, bariatric surgery, medicines, supplements and any history of inherited blood conditions in either biological parent.
Treatment options
Treatment depends on cause, severity, gestation, symptoms and how close birth is.
Iron tablets
Prescribed oral iron is commonly used for iron deficiency anaemia. It may darken stools and can cause constipation, diarrhoea, nausea, tummy pain or heartburn. Taking it exactly as advised matters because some foods, drinks and medicines reduce absorption.
If side effects are difficult, ask for help rather than stopping silently. The prescriber may adjust the formulation, timing or dose, or consider other options.
Intravenous iron
Intravenous iron may be considered when tablets are not tolerated, not absorbed, anaemia is more severe, or there is limited time before birth. It is given under medical supervision because suitability and monitoring depend on the individual.
B12 and folate treatment
B12 deficiency may need injections or tablets depending on cause. Folate deficiency is usually treated with folic acid tablets. If both B12 and folate are possible, clinicians usually check and treat carefully because folate alone can improve the blood count while B12-related nerve problems continue.
Severe anaemia
Severe anaemia, major bleeding or symptoms affecting heart or breathing may need urgent assessment. Rarely, hospital treatment or blood transfusion may be needed. The maternity team will balance the mother’s symptoms, gestation, cause and birth plan.
Iron, B12, folate and diet
Diet can support treatment and prevention, but it may not be enough on its own once anaemia is established.
Iron-rich foods include lean meat, fish, eggs, beans, lentils, chickpeas, tofu, fortified breakfast cereals, wholemeal bread, nuts, seeds, dried fruit and dark-green leafy vegetables. Vitamin C-rich foods such as oranges, berries, peppers, tomatoes and broccoli can help absorb plant-based iron.
Tea and coffee can reduce iron absorption if taken with meals or iron tablets. Calcium-rich foods and supplements may also interfere with iron absorption when taken at the same time. Follow midwife, GP or pharmacist advice about spacing iron from other medicines or supplements.
Vitamin B12 is found in meat, fish, eggs, dairy and fortified foods. People following vegan diets should use reliable fortified foods or pregnancy-safe B12 supplements. Folate is found in green vegetables, beans, peas and fortified foods, but folic acid supplementation is still recommended around conception and early pregnancy according to UK pregnancy guidance.
Follow-up and prevention
Follow-up blood tests check whether haemoglobin and iron stores are improving. Symptoms may improve before stores are fully restored, so stopping treatment early can allow anaemia to return.
If anaemia does not improve as expected, the team may review adherence, absorption, bleeding, diagnosis and whether another cause is present. People with previous severe anaemia, multiple pregnancy, late booking, close pregnancies, inherited blood conditions, heavy bleeding or planned caesarean birth may need closer planning before delivery.
After birth, anaemia can make recovery, breastfeeding, mood and everyday care harder. Postnatal follow-up is important if there was anaemia in pregnancy, heavy bleeding at birth, ongoing symptoms or difficulty tolerating treatment.
When to seek urgent advice
Contact your midwife, maternity triage unit, GP or NHS 111 urgently if you are pregnant and have severe breathlessness, chest pain, fainting, a racing heartbeat that does not settle, severe weakness, black or bloody stools, vomiting blood, heavy vaginal bleeding, severe headache, visual symptoms, or you feel acutely unwell.
Follow your local maternity advice about reduced fetal movements. If your baby’s movements are reduced, changed or worrying, contact maternity triage promptly rather than waiting. Call 999 in a life-threatening emergency.
Sources
- NICE, Antenatal care recommendations
Relevance: Supports routine antenatal full blood count timing, screening and person-centred pregnancy care. - NHS, Iron deficiency anaemia
Relevance: Supports symptoms, causes, oral iron treatment, diet advice, side effects and safety cautions. - NHS, Vitamin B12 or folate deficiency anaemia
Relevance: Supports B12 and folate symptom, treatment and complication sections. - NHS, Pregnancy vitamins and supplements
Relevance: Supports pregnancy-specific supplement and nutrition advice, including folic acid and pregnancy diet planning. - Mayo Clinic, Anemia: symptoms and causes (mayoclinic.org guidance page, link unavailable during validation)
Relevance: Benchmark condition-page source for anaemia definition, causes, symptoms, risk factors and complications.
Disclaimer
Educational only. Results vary. Not a cure.