Prophylactic anticoagulation for preterm premature rupture of membranes: a decision analysis

Abstract

Background: The current standard of care in the setting of preterm premature rupture of membranes involves antenatal hospitalization until delivery. The reduced physical activity during this time compounds the heightened risk for venous thromboembolism in pregnancy. Prophylactic anticoagulation can decrease this risk of venous thromboembolism; however, this benefit must be balanced against the risks of precluding neuraxial analgesia or increasing the risk of postpartum hemorrhage.

Objective: The objective of this study was to determine the optimal modality for venous thromboembolism prophylaxis during hospitalization for preterm premature rupture of membranes using a decision analysis model.

Study design: A decision-analytical Markov model was constructed using the TreeAge software comparing the use of unfractionated heparin, low-molecular-weight heparin or no anticoagulation in women with a singleton pregnancy who were hospitalized for preterm premature rupture of membranes after 24 weeks and remained hospitalized until delivery. Maternal outcomes examined included attainment of neuraxial analgesia (vs no analgesia for vaginal delivery or general anesthesia for cesarean delivery), venous thromboembolism, postpartum hemorrhage, and maternal death. Probabilities and utilities were derived from existing literature. Sensitivity analyses were performed to interrogate model assumptions, and a Monte Carlo probabilistic sensitivity analysis was performed to examine the robustness of the model.

Results: In this decision-analytical model, no prophylactic anticoagulation maximized maternal utilities. Clinical outcomes among a theoretical cohort of 100,000 women are shown in the Table. The 1- and 2-way sensitivity analyses supported this conclusion. Monte Carlo probabilistic sensitivity analysis indicated that no prophylaxis was the preferred choice in 56% of simulations, unfractionated heparin in 34% of simulations, and low-molecular-weight heparin in 10% of simulations.

Conclusion: Our results do not support the routine use of prophylactic anticoagulation in women admitted to the hospital for preterm premature rupture of membranes. These findings can be used to inform clinical decisions when admitting low-risk singleton pregnancies to the hospital in the setting of preterm premature rupture of membranes.

Keywords: antepartum hospitalization; decision analysis; pregnancy complication; preterm premature rupture of membranes (PPROM); prophylactic anticoagulation.