Haemoglobinopathies in pregnancy — structured SAQ (15 marks)

(a) Antenatal plan (5 marks)

One mark per point, maximum five. ^[1][2]

• Multidisciplinary team: haematology, obstetrics, anaesthetics, midwifery, with a named lead and joint clinic. Counsel on the raised maternal and perinatal risks (Oteng-Ntim Blood 2015 meta-analysis: maternal mortality RR 5.98, pre-eclampsia RR 2.43, stillbirth RR 3.94, SGA RR 3.72, preterm RR 2.21).^[1][2]
• Thromboprophylaxis: low-molecular-weight heparin (e.g. enoxaparin 40 mg daily) throughout pregnancy, dose-adjusted for weight and renal function, continued for 6 weeks postpartum.^[1]
• Surveillance: serial growth scans every 4 weeks from 24 weeks; low threshold for admission in crisis; midstream urine each trimester; vaccination status (pneumococcus, meningococcus, haemophilus, hepatitis B, influenza).^[1]
• Medications: folic acid 5 mg daily (lifelong in HbSS); review hydroxyurea — discontinue preconception and avoid in pregnancy.^[1]
• Plan delivery: in a unit with haematology, anaesthetics and neonatal support; avoid prolonged labour; keep warm, well hydrated and oxygenated; continuous fetal monitoring; regional anaesthesia preferred.^[1]

(b) Acute chest syndrome (5 marks)

One mark per point, maximum five. ^[1]

• Diagnosis: acute chest syndrome — fever, pleuritic chest pain, hypoxia (saturation 92 percent) and new infiltrates on chest X-ray in a sickle cell disease patient. The leading cause of sickle cell mortality.^[1]
• Analgesia within 30 minutes: morphine 5 to 10 mg intravenously, titrated; patient-controlled analgesia in established crises. Avoid pethidine (metabolite lowers seizure threshold).^[1]
• Oxygen to maintain saturation above 94 percent or above baseline; incentive spirometry every 2 hours while awake to prevent atelectasis.^[1]
• Broad-spectrum antibiotics covering encapsulated organisms (functional asplenia) and atypicals (e.g. ceftriaxone plus azithromycin) after blood cultures.^[1]
• Transfusion for severe or worsening hypoxia — simple transfusion to raise Hb, or exchange transfusion to reduce HbS below 30 percent if hypoxia is severe, worsening or with multilobar involvement. Phenotypically matched blood from the start.^[3]

(c) Transfusion strategy (3 marks)

One mark per point, maximum three. ^[1][3]

• Indications: severe anaemia (Hb well below baseline), acute chest syndrome, stroke, splenic sequestration, perioperative cover. Prophylactic transfusion is not routine in most uncomplicated sickle cell pregnancies — transfuse on indication.^[1][3]
• Phenotypic matching: extended phenotypically matched blood (ABO, Rh, Kell, Kidd, Duffy) from the first transfusion to limit alloimmunisation, which is common and dangerous in sickle cell disease.^[3]
• Risks: alloimmunisation, delayed haemolytic transfusion reaction (DHTR), iron overload, transfusion-transmitted infection. Identify preformed antibodies early in pregnancy.^[3]

(d) Postpartum contraception (2 marks)

One mark per point, maximum two. ^[1][5]

• Progestogen-only methods are safe in sickle cell disease — progestogen-only pill, depo-medroxyprogesterone, progestogen implant, levonorgestrel intrauterine system.^[1][5]
• Combined hormonal contraception is generally avoided because of the raised VTE risk in sickle cell disease, but may be considered in well-controlled, non-smoking women after individual risk assessment. The levonorgestrel intrauterine system is an excellent option.^[5]