Management of Haemoglobinopathy in Pregnancy: A Complex Case of Hb H Disease with Alloimmunisation

Patient: 42-year-old woman with Hb H disease (baseline Hb 70–80 g/L).

History: Hb drop to 20s with parvovirus 8 years ago; intermittent transfusions with viral illnesses; first pregnancy abroad 7 years ago with peripartum transfusion.

Immunohematology: Known anti-Cw, later developed anti-Fyb after a 2-unit transfusion in current pregnancy.

Iron/bone health: Liver iron overload (moderate-severe on LIC), cardiac T2* MRI within the last year normal; on deferiprone pre-pregnancy (allergic to deferasirox); osteopenia.

Current pregnancy: Now 14 weeks. On folic acid and vitamin D. Aspirin started at 12 weeks. Deferiprone stopped. Red-cell genotyping completed; partner screened and is α-thalassaemia carrier (single gene deletion). Couple declined prenatal diagnosis.

Plan so far: Transfuse to keep Hb ≥90–100 g/L; LMWH prophylaxis from 28 weeks and for 6 weeks postpartum; antibody titers again at 28 weeks; genotype-matched, antigen-negative blood (Cw- and Fyb- negative); fetal medicine follow-up with MCA Dopplers if titers rise; delivery around 38–40 weeks with cross-matched blood available; consider DFO infusion if needed; neonatal cord blood DAT, Hb, bilirubin, and α-thalassaemia testing.

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Questions and concise, evidence-based answers

Q1. What pre-conception/early pregnancy counselling is indicated for a woman with Hb H disease?

Partner testing and genetic risk: Test for α-thalassaemia deletions. If the partner has a single α-globin gene deletion (−α/αα), the child has a 25% risk of Hb H disease; if partner has α0 trait (--/αα), there is a risk of Hb Bart's hydrops. Offer genetic counselling and discuss prenatal options. [1]
Transfusion planning: Early antibody screen and extended phenotype/genotype, with plan for antigen-negative, genotype-matched units due to anti-Cw and later anti-Fyb. [2]
Iron overload and chelation: Stop deferiprone/dfx when attempting conception or once pregnant; DFO can be considered in 2nd/3rd trimester if there is significant iron burden or clinical need. Cardiac T2* thresholds from RCOG GTG 66 guide chelation decisions. [3]
VTE and obstetric risks: Explain higher VTE risk in pregnancy and in thalassaemia; plan postpartum LMWH for 6 weeks if risk factors present; consider antepartum LMWH if cumulative risk warrants it. [4]

Q2. What screening and monitoring schedule is appropriate?

Maternal: Antibody screen at booking and 28 weeks, with more frequent monitoring if clinically significant antibodies present. For most non-D/c/K antibodies, repeat at 28 weeks; follow standard titer pathways for clinically significant antibodies and involve fetal medicine. [2]
Fetal: If titers reach referral thresholds or rise, start MCA-PSV Dopplers from ~20 weeks and manage per fetal medicine unit (FMU) protocols; consider IUT if MCA-PSV >1.5 MoM. [2]
Iron: Repeat LIC assessment in late 2nd/early 3rd trimester if previously high; cardiac T2* MRI is usually pre-pregnancy, but results guide whether chelation is safe/required. [3]

Q3. How should transfusion targets be set during pregnancy?

Target Hb: Maintain pre-transfusion Hb around 100 g/L to support fetal growth and maternal well-being; practical lower limit ≥90 g/L if logistics or antibodies limit supply. [5]
Compatibility: Provide C^w-negative and Fyb-negative, extended genotype-matched units; liaise early with the transfusion lab. [2]

Management of Haemoglobinopathy in Pregnancy: A Complex Case of Hb H Disease with Alloimmunisation

Questions and concise, evidence-based answers

Q1. What pre-conception/early pregnancy counselling is indicated for a woman with Hb H disease?

Q2. What screening and monitoring schedule is appropriate?

Q3. How should transfusion targets be set during pregnancy?

Q4. What is the clinical significance of anti-Cw and anti-Fyb in pregnancy?