Management of Beta Thalassaemia in Pregnancy
Definitions
Thalassaemia major: women requiring more than 7 transfusion episodes/year. Thalassaemia intermedia: women requiring 7 or fewer transfusions/year, or none. Thalassaemia carriers (trait) do not require transfusion and are outside the scope of this guideline.
Preconception Care
- Discuss and document pregnancy intentions at every thalassaemia team visit; screen for end-organ damage before conception (Grade D).
- Cardiac: echocardiogram, ECG, and cardiac T2* MRI before pregnancy. Aim for cardiac T2* >20 ms (minimal iron); T2* <10 ms carries a materially increased risk of cardiac decompensation and warrants multidisciplinary discussion before conception.
- Liver: assess liver iron via FerriScan® or liver T2*; target liver iron <7 mg/g dry weight (dw). If liver iron >15 mg/g dw, low-dose desferrioxamine chelation should start between 20–28 weeks' gestation.
- Endocrine: screen for diabetes (target serum fructosamine <300 nmol/L for ≥3 months preconception, equivalent to HbA1c <43 mmol/mol — fructosamine is preferred as HbA1c is diluted by transfused blood) and hypothyroidism (aim euthyroid preconception, Grade B).
- Bone: offer a bone density scan; optimise vitamin D.
- Chelation: deferasirox and deferiprone are ideally stopped 3 months before conception (limited human safety data, though animal studies of deferasirox showed no teratogenicity). Desferrioxamine is the only chelator with an evidence base for use in pregnancy — avoided in the first trimester, used safely at low dose from 20 weeks.
- Folic acid 5 mg daily from 3 months preconception (Grade A) — women with thalassaemia have markedly higher folate demand.
- Hepatitis B vaccination for HBsAg-negative women who are/may be transfused; hepatitis C status determined. Splenectomised women: penicillin (or equivalent) prophylaxis plus pneumococcal, Hib and meningococcal C vaccination.
- Red cell antibody screening: alloimmunisation occurs in 16.5% of individuals with thalassaemia.
Antenatal Care
- Monthly multidisciplinary review until 28 weeks, then fortnightly.
- Ultrasound: early viability scan at 7–9 weeks, routine first-trimester scan (11–14 weeks), detailed anomaly scan (18–20+6 weeks), then serial fetal biometry every 4 weeks from 24 weeks (chronic anaemia impairs placental nutrient transfer and predisposes to fetal growth restriction).
- Transfusion (major): maintain pretransfusion haemoglobin ≥100 g/L.
- Transfusion (intermedia): initiate regular transfusion if worsening anaemia or FGR develops; once started, targets mirror thalassaemia major. If untransfused and Hb ≥80 g/L at 36 weeks, transfusion can often be deferred until delivery; if Hb <80 g/L, give a top-up transfusion (2 units) at 37–38 weeks.
- Cardiac monitoring: women with myocardial iron loading undergo regular cardiology review with careful ejection fraction monitoring (Grade C). Those at highest risk of cardiac decompensation (T2* <20 ms) should start low-dose subcutaneous desferrioxamine (20 mg/kg/day, ≥4–5 days/week) from 20–24 weeks (Grade C). Specialist cardiac assessment for all thalassaemia major women at 28 weeks and as appropriate thereafter.
- Thromboprophylaxis: low-dose aspirin (75 mg/day) if splenectomised or platelet count >600 × 10⁹/L; add prophylactic LMWH if both apply, and during any antenatal hospital admission.
Intrapartum and Postpartum Care
- Continuous intrapartum electronic fetal monitoring; active management of the third stage of labour (Grade A) to minimise blood loss.
- IV desferrioxamine 2 g over 24 hours throughout labour in women with thalassaemia major.
- Thalassaemia itself is not an indication for caesarean section; timing/mode of delivery follows standard national guidance.
- Postpartum: women with thalassaemia are considered high risk for venous thromboembolism (Grade D) due to circulating abnormal red cell fragments — LMWH prophylaxis for 7 days after vaginal delivery or 6 weeks after caesarean section. Breastfeeding is safe and encouraged; desferrioxamine is secreted in breast milk but is not orally absorbed by the infant.
High-Yield Exam Points
- Major = >7 transfusions/year; intermedia = ≤7/year (or untransfused).
- Pretransfusion Hb target throughout pregnancy: ≥100 g/L.
- Cardiac T2* <10 ms = highest risk of cardiac decompensation; >20 ms = minimal cardiac iron (goal).
- Liver iron target <7 mg/g dw preconception; >15 mg/g dw signals high risk of myocardial iron loading and triggers chelation from 20–28 weeks.
- Desferrioxamine is the only iron chelator with a pregnancy safety evidence base; deferasirox and deferiprone should be stopped 3 months before conception.
- High-dose folic acid 5 mg daily from 3 months preconception (Grade A).
- Intrapartum IV desferrioxamine 2 g/24h; active third-stage management is Grade A evidence to reduce blood loss.
- Alloimmunisation prevalence in thalassaemia: 16.5%.
Source: RCOG Green-top Guideline No. 66 (Archived — content below remains clinically relevant unless a successor is found) (March 2014 (first edition; scheduled review process was due to commence 2017 — no confirmed RCOG successor identified as of this writing, though the British Society for Haematology published a 2023 guideline, "Guideline for the Management of Conception and Pregnancy in Thalassaemia Syndromes," which may supersede it in practice))
Read the original on rcog.org.uk
MRCOG AI is an independent educational tool. It is not affiliated with, endorsed by, or connected to the Royal College of Obstetricians and Gynaecologists (RCOG).