Postoperative venous thromboembolism following cesarean delivery: prevalence, pathophysiology, diagnosis, treatment, and prevention.

Abstract

Venous thromboembolism contributes to approximately 10% of pregnancy-associated deaths in the United States, with the highest incidence rate in the immediate postpartum period. Cesarean deliveries are associated with 4-fold relative risk of venous thromboembolism vs vaginal delivery. While most patients have some evidence of thrombosis in the pelvic veins after cesarean delivery, only a small proportion of patients (2.6-4.3 per 1000 deliveries) develop a clinically relevant venous thromboembolism. We outline the normal physiologic process of postcesarean hemostasis and the pathways by which aberrant balance in hemostasis may result in venous thromboembolism. With respect to diagnosis, vascular ultrasound remains the cornerstone of deep vein thrombosis diagnosis, while ventilation/perfusion studies and computed tomographic angiography are bedrocks of pulmonary embolism diagnosis. Venous thromboembolism prediction rules have not been validated in the postcesarean population and high rates of elevated D-dimer concentrations in the weeks after cesarean delivery limit their use. For the treatment of postpartum venous thromboembolism, low-molecular-weight heparin is the mainstay of acute management, but a wide range of alternative agents are now available, including warfarin and direct oral anticoagulants. In contemporary practice, there is large variation in the use of postpartum pharmacologic prophylaxis within the United States and internationally. Whether broader use of postpartum pharmacologic prophylaxis reduces the incidence of postcesarean venous thromboembolism with acceptable rates of adverse events (eg, bleeding complications) is unclear; observational evidence has come to conflicting conclusions. There is an urgent need for further study of the effectiveness of postpartum prophylaxis, and its optimal agent, dose, and duration, in randomized trials. Contemporary guidelines regarding which patients should receive postpartum pharmacologic prophylaxis are based largely on expert opinion; well-validated postpartum venous thromboembolism prediction models and patient preference data are needed to inform risk stratification and counseling.