A comparison of pregnancy-specific risk scoring systems for venous thromboembolic pharmacoprophylaxis in hospitalized maternity patients

Objective: Venous thromboembolism (VTE) remains a leading cause of maternal mortality. The American College of Obstetricians and Gynecologists (ACOG) and the Royal College of Obstetricians & Gynecologists (RCOG) have proposed pregnancy-specific risk scoring guidelines for antepartum (AP) and postpartum (PP) thromboprophylaxis. We compared the impact of scoring thresholds and their potential preventative effect. Study design: We conducted a retrospective cohort study of hospitalized maternity patients over a 4-month period. Patients were assigned an AP and PP risk score using each guideline. Hospitalization-associated VTE was accessed over a 6-year period. Comparison was by Fischer’s exact and Chi Square tests. Results: 638 women were included. Of AP patients, 20% met pharmacoprophylaxis criteria for baseline characteristics and 100% for length of stay using RCOG, and 12% met phrarmacoprophylaxis criteria using ACOG (p <.001). For PP patients, 53% met criteria for RCOG compared to 24% using ACOG (p <.001). If pharmacoprophylaxis were performed at a threshold 1 point above recommendation, 7% of AP patients and 11% of PP women would meet ACOG criteria. This increased ACOG threshold captured all cases of VTE following hospitalization. Conclusion: In our population, using ACOG prophylaxis guidelines at an increased threshold would have potentially prevented all hospitalization related VTE without excessive anti-coagulation.