Iron deficiency anaemia in pregnancy

Red Flags

Severe anaemia (Hb <70 g/L) at any gestation — admit; investigate other causes; IV iron and possibly transfusion; obstetric and haematology review^[1]
Anaemia with cardiac decompensation (tachycardia, dyspnoea, oedema) — emergency obstetric and cardiology review; consider transfusion^[1]
Anaemia at term in labour — IV iron pre-delivery if Hb 70–100 g/L; cross-match and have transfusion ready; active third stage management^[1]
No response to oral iron after 4 weeks of adequate dose — investigate adherence, malabsorption, ongoing blood loss; consider IV iron and parasitology screen^[1]

First-line treatment

Interventions

Universal iron supplementation in pregnancy^[1]
Daily oral elemental iron 30–60 mg + folic acid 400 µg from booking through delivery (FOGSI/WHO); higher dose 60–120 mg in established deficiency or high-prevalence settings
Dietary advice and counselling^[1]
Iron-rich foods (dark green leafy vegetables, pulses, jaggery, eggs, meat where consumed); vitamin C with iron meal; avoid tea/coffee within 1 hour of iron; treat helminthic infection in endemic areas
Transfusion of packed red cells^[1]
Reserved for Hb <70 g/L, symptomatic anaemia, active haemorrhage, or imminent delivery without time for iron repletion; 1 unit at a time and reassess; avoid where IV iron sufficient
Active third-stage management and postpartum iron continuation^[1]
Oxytocin 10 IU IM after delivery, controlled cord traction, uterine massage; continue oral or IV iron postpartum to repletion (ferritin >50 µg/L)

First-line drug therapy

Drug	Class	Adult	Paediatric	Notes
Oral elemental iron (ferrous sulphate, fumarate, gluconate, or polymaltose)^[1]	Iron salt	Established IDA: 100–200 mg elemental iron PO daily (or alternate-day for tolerance); empty stomach with vitamin C; reassess Hb in 2–4 weeks	Adolescent pregnancies: 60–120 mg elemental iron daily	First-line for mild–moderate IDA; nausea, constipation common — alternate-day dosing improves absorption per hepcidin physiology; iron polymaltose has fewer GI side effects
Intravenous iron — ferric carboxymaltose, iron sucrose, ferric derisomaltose^[1]	Parenteral iron	Ferric carboxymaltose 1000 mg IV single dose (max 1000 mg/week, 2000 mg total); iron sucrose 200 mg IV per session × multiple sessions to total dose; ferric derisomaltose up to 20 mg/kg single infusion	—	Indications: oral iron intolerance or non-response, severe anaemia (Hb <90 g/L) at >34 weeks, malabsorption, or rapid repletion before delivery. Avoid first trimester unless severe; monitor for hypersensitivity, hypophosphataemia (FCM)

Oral elemental iron (ferrous sulphate, fumarate, gluconate, or polymaltose)^[1]

Iron salt

Adult: Established IDA: 100–200 mg elemental iron PO daily (or alternate-day for tolerance); empty stomach with vitamin C; reassess Hb in 2–4 weeks
Paediatric: Adolescent pregnancies: 60–120 mg elemental iron daily

First-line for mild–moderate IDA; nausea, constipation common — alternate-day dosing improves absorption per hepcidin physiology; iron polymaltose has fewer GI side effects

Intravenous iron — ferric carboxymaltose, iron sucrose, ferric derisomaltose^[1]

Parenteral iron

Adult: Ferric carboxymaltose 1000 mg IV single dose (max 1000 mg/week, 2000 mg total); iron sucrose 200 mg IV per session × multiple sessions to total dose; ferric derisomaltose up to 20 mg/kg single infusion
Paediatric: —

Indications: oral iron intolerance or non-response, severe anaemia (Hb <90 g/L) at >34 weeks, malabsorption, or rapid repletion before delivery. Avoid first trimester unless severe; monitor for hypersensitivity, hypophosphataemia (FCM)

Safety-net

Take iron tablets daily — missing doses delays recovery; alternate-day dosing improves absorption and reduces nausea, ask your clinician^[1]
Eat iron-rich foods with vitamin C (citrus, tomatoes); avoid tea or coffee within an hour of iron tablets^[1]
If tablets cause severe nausea, constipation, or you cannot tolerate them — return for review; intravenous iron is available and effective^[1]

Referral criteria

Severe anaemia (Hb <70 g/L) at any gestation, or Hb <80 g/L third trimesterJoint obstetric and haematology review; admission for IV iron ± transfusion^[1]
Non-response or partial response to oral iron at 4 weeksObstetric assessment for IV iron and aetiology workup^[1]
Suspected thalassaemia, sickle cell, or other haemoglobinopathy on smear or electrophoresisHaematology and antenatal genetics^[1]
Postpartum haemorrhage with subsequent anaemia (Hb <90 g/L)Obstetric review; IV iron with consideration of single-dose ferric carboxymaltose^[1]

Clinical summary

Screening, oral and intravenous iron repletion, and transfusion thresholds for iron deficiency anaemia in pregnancy and the puerperium.

References

1.FOGSI Good Clinical Practice Recommendations on Management of Iron Deficiency Anaemia in Pregnancy (2017, refreshed 2022); BSH 2020 UK guideline; WHO Antenatal Care Recommendations (2022)