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Heparin-Based Obstetric Thromboprophylaxis Protocol
Quick Takes
- Pregnant and postpartum patients are at increased risk of acute venous thromboembolism (VTE).
- A more selective risk-stratification protocol successfully reduced overall use of enoxaparin chemoprophylaxis by approximately 50%.
- The more selective risk-stratification protocol was associated with reduced wound hematoma rates with no change in VTE.
Study Questions:
What are the outcomes associated with a more selective versus standard risk-stratified approach to a heparin-based obstetric thromboprophylaxis protocol?
Methods:
The authors conducted a retrospective observational study of 17,489 patients who underwent pregnancy delivery at a single tertiary care center between 2016–2018 (standard risk-stratification protocol) and December 2021–May 2023 (selective risk-stratification protocol). Patients receiving therapeutic anticoagulation were excluded. The more selective protocol required more risk factors to qualify for VTE chemoprophylaxis and no longer included obesity as an independent venous thromboembolism (VTE) risk factor. The chemoprophylactic regimen included enoxaparin 40 mg once or twice daily starting on postpartum day 1 and continued through hospital discharge (typically up to 96 hours). The primary outcome was the clinical diagnosis of wound hematoma up to 6 weeks postpartum. The secondary outcome was a new diagnosis VTE up to 6 weeks postpartum.
Results:
Of the 17,489 patients included in the analysis, 12,430 (71%) were treated under the standard risk-stratification protocol, while 5,029 (29%) were treated under the more selective risk-stratification protocol. Rates of chemoprophylaxis decreased from 16% to 8% when transitioning from the standard to selective risk-stratification protocol. Compared to the standard protocol, the more selective protocol was associated with a decrease in any wound hematoma (0.7% vs. 0.3%, adjusted odds ratio, 0.38; 95% confidence interval [CI], 0.21-0.67). There was no significant increase in VTE (0.1% in both arms).
Conclusions:
The authors conclude that a more selective risk-stratification approach to chemoprophylaxis for VTE in postpartum patients was associated with decreased rates of wound hematoma without any increase in VTE risk.
Perspective:
Pregnancy and the postpartum period is one of the strongest risk factors for acute VTE, related to hormonal changes, compression of central venous blood flow, and immobility. For patients with additional risk factors (e.g., prior VTE, nephrotic syndrome), use of chemoprophylaxis to prevent VTE is common practice. However, anticoagulation therapy can also cause bleeding complications, including wound hematoma at the site of delivery or cesarean incision. This pre-post analysis of a risk-stratification change at one busy delivery center demonstrated a significant reduction in wound bleeding complications without any increase in VTE risk when fewer patients received chemoprophylaxis. These findings are analogous to a movement in the past 10 years towards more selective use of chemoprophylaxis for hospitalized adult medical patients, another high-risk clinical scenario for acute VTE. Anticoagulation stewardship teams at health systems should re-assess current VTE chemoprophylaxis practices for postpartum patients, assessing if overuse may be leading to unnecessary bleeding complications.
Clinical Topics: Pulmonary Hypertension and Venous Thromboembolism, Vascular Medicine
Keywords: Cardio-Obstetrics, Postpartum Period, Venous Thromboembolism
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