Pregnancy‐related venous thromboembolism and HIV infection

Objective To assess risk factors for venous thromboembolism (VTE) in African women in order to guide thromboprophylaxis. Methods A case‐control study was performed at a specialist obstetric unit in South Africa from July 1, 2017 to June 30, 2020. We identified 128 cases with VTE and 640 controls, matched for gestation. Results Prepartum risk factors associated with VTE included; medical comorbidities (odds ratios [OR] 5.32, 95% confidence intervals [CI] 1.82–15.56), human immunodeficiency virus (HIV) (OR 2.84, 95% CI 1.50–5.41), and hospital admission or immobility (OR 5.33, 95% CI 1.17–24.22). Postpartum, the following were identified as significant risk factors; medical comorbidities (OR 23.72, 95% CI 8.75–64.27), hospital admission or immobility (OR 13.18, 95% CI 5.04–34.49), systemic infection (OR 4.48, 95% CI 1.28–15.68), HIV (OR 3.20, 95% CI 1.49–6.87), pre‐eclampsia and fetal growth restriction (OR 2.74, 95% CI 1.18–6.36), and postpartum hemorrhage (OR 4.38, 95% CI 1.75–10.97). Antiretroviral therapy, opportunistic infections, and viral load >50 copies/ml, however, were not associated with VTE risk among HIV‐infected participants. Conclusion HIV was a significant risk factor for pregnancy‐related thrombosis. This was independent of traditional HIV risk factors. As such, future studies are recommended to explore the mechanisms of thrombosis associated with HIV infection. Synopsis HIV infection was associated with an approximately three‐fold increased risk for venous thromboembolism among African pregnant and postpartum women.