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.