Sickle Cell Disease in Pregnancy

Sickle cell disease in pregnancy is a chronic inherited haemoglobinopathy (HbSS, HbSC, HbS beta thalassaemia) in a pregnant woman, with vaso-occlusive crises, haemolysis and organ damage. Pregnancy raises the risk of crisis, infection, venous thromboembolism, preeclampsia, stillbirth and maternal death.

• Risk factors for severe course: HbSS, previous crises, renal disease, hypertension, lung disease.
• Fetal loss is higher than in women with normal haemoglobin.
• Planned care with early booking lowers risk.

Women have pallor, jaundice, bone pain, fatigue and recurrent infections, with a baseline haemoglobin of 6 to 9 g/dL in HbSS. Examine for splenomegaly, leg ulcers, hypertension and growth.

• Pain crises, often in bones, chest or abdomen.
• Dactylitis history and early splenic loss.
• Differential diagnosis: sickle cell crisis, appendicitis, pyelonephritis, cholecystitis, abruption, preeclampsia, HELLP syndrome, malaria.
• Complications: pain crisis, acute chest syndrome, infection, severe anaemia, stroke, venous thromboembolism, preeclampsia, fetal growth restriction, preterm birth, stillbirth, maternal death.

The approach is confirmation of genotype and baseline organ assessment.

• Haemoglobin electrophoresis or HPLC; sickling test where electrophoresis is unavailable.
• Full blood count, reticulocytes, ferritin, urea, creatinine, liver enzymes, urine protein to creatinine ratio, blood group with antibody screen.
• Monthly urine culture; malaria test at each fever; partner haemoglobin testing.
• Growth scans every 4 weeks from 24 weeks; uterine artery Doppler at 20 to 24 weeks.

The principle is preventive care, early treatment of crisis and infection, and planned delivery.

• Supportive: avoid dehydration and cold; drink 3 litres daily; insecticide treated net; rest; avoid smoking and alcohol; vaccinations (pneumococcal conjugate, influenza, hepatitis B, meningococcal) if not given.
• Pharmacological: folic acid 5 mg oral daily; aspirin 75 to 150 mg oral at night from 12 weeks to 36 weeks; enoxaparin 40 mg subcutaneous daily during admission and for 6 weeks after delivery; malaria prevention: proguanil 100 mg oral daily with folic acid 5 mg, or sulfadoxine-pyrimethamine 3 tablets (500 mg and 25 mg each) oral monthly from 13 weeks with folic acid reduced to 400 micrograms daily; penicillin V 250 mg oral 12-hourly if there is functional asplenia; ferrous sulphate 200 mg oral 8-hourly only if ferritin is low; stop hydroxyurea before conception; treat asymptomatic bacteriuria with amoxicillin 500 mg oral 8-hourly for 7 days.
• Procedures: top up or exchange transfusion for severe anaemia, acute chest syndrome, previous stroke or twin pregnancy, targeting haemoglobin 10 g/dL and HbS below 40 percent; induction of labour at 38 to 40 weeks.
• Special groups: HbSC disease has milder anaemia but similar crisis risk; use compatible, phenotype matched blood if antibodies are present; women with renal disease or hypertension use methyldopa 250 to 500 mg oral 8-hourly (maximum 3 g daily).
• Red flags: pain crisis, fever above 38 degrees Celsius, chest pain, cough, breathlessness, headache, weakness, haemoglobin below 6 g/dL or a fall of 2 g/dL.
• Follow-up: review every 2 weeks; haemoglobin monthly; growth scans every 4 weeks from 24 weeks; postnatal contraception with depot medroxyprogesterone 150 mg IM every 13 weeks; neonatal sickle screening.