Sickle Cell Disease in Pregnancy
A 27-year-old primigravida with homozygous sickle cell disease attends antenatal clinic at 16 weeks gestation. She takes folic acid, penicillin prophylaxis, and low-dose aspirin begun at 12 weeks, and had two vaso-occlusive crises last year. Hemoglobin is 82 g/L, blood pressure is 108/64 mm Hg, and urinalysis shows no protein. Apart from acute painful crisis, which complication is she most likely to develop?
- A.Acute chest syndrome
- B.Preeclampsia before 34 weeks
- C.Deep venous thrombosis
- D.Urinary tract infectionCorrect
Explanation
RCOG Green-top Guideline No. 61 states that acute painful crisis is the most frequent complication of sickle cell disease in pregnancy, affecting 27% to 50% of women, and once crisis is set aside urinary tract infection is the commonest problem. The same guideline notes an increased incidence of urinary tract infection and asymptomatic bacteriuria and therefore requires urinalysis at every antenatal visit with a midstream urine sent for culture monthly. Two mechanisms combine: sickling in the hypoxic, acidic, hypertonic renal medulla produces papillary damage with impaired urinary concentration and acidification, and normal pregnancy adds progesterone-mediated ureteric relaxation, mechanical compression, and urinary stasis. Functional hyposplenism from repeated splenic infarction further weakens defence against encapsulated organisms. Asymptomatic bacteriuria is treated whenever it is found, because untreated it progresses to pyelonephritis and readily precipitates a painful crisis. Acute chest syndrome is the leading cause of maternal death in this group but complicates a much smaller proportion of pregnancies. Preeclampsia is more frequent than in unaffected women, which is why low-dose aspirin from 12 weeks is advised, yet early-onset disease affects a minority and her blood pressure and urinalysis are currently normal. Venous thromboembolism risk is raised enough to justify low-molecular-weight heparin during any antenatal admission, but events remain uncommon. Other core measures are folic acid 5 mg daily, avoiding iron unless deficiency is proven, serial growth scans, stopping hydroxycarbamide before conception, and urgent assessment of any temperature above 37.5 °C.
Why each option
- A.
- Acute chest syndrome is the most lethal complication and a leading cause of maternal death, but it affects far fewer pregnancies than urinary infection.
- B.
- Preeclampsia risk is increased and justifies aspirin from 12 weeks, yet early-onset disease still occurs in only a minority of these pregnancies.
- C.
- Venous thromboembolism is increased and warrants heparin during admissions, but it remains much less common than urinary infection.
- D.
- Correct. Sickle nephropathy, pregnancy-related urinary stasis, and hyposplenism make urinary tract infection the commonest complication after painful crisis.
Reference: RCOG Green-top Guideline No. 61, Management of Sickle Cell Disease in Pregnancy, 2011; UpToDate 2025, Sickle cell disease in pregnancy: Antenatal care
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