(667) Timing of postpartum pharmacologic thromboprophylaxis relative to delivery and anesthesia

To describe the rate of adherence to obstetric (OB) and anesthesia (ANE) guidelines for timing of postpartum pharmacologic prophylaxis initiation. Secondarily, to evaluate the association between guideline adherence and venous thromboembolism (VTE) and complications.

Study Design: Retrospective cohort of patients delivering at a single academic center from 2015-2023 receiving postpartum low molecular weight heparin (LMWH) prophylaxis. Those with an antepartum VTE or on therapeutic anticoagulation were excluded. OB guideline adherence was defined as LMWH initiation within 4-6 hours after vaginal, or 6-12 hours after cesarean, delivery. ANE guideline adherence was defined as LMWH initiation ≥12 hours post-neuraxial ANE placement and ≥4 hours post-neuraxial removal. Secondary outcomes included VTE (pulmonary embolism or deep vein thrombosis), readmission, reoperation, and wound complications (hematoma, seroma, or infection) within 6 weeks postpartum. Median time from delivery and neuraxial ANE to LMWH initiation, and rate of adherence to guidelines was assessed. Multivariable models estimated the association between guideline adherence and outcomes.

Results: Of 7,414 included, 4,894 (66%) underwent cesarean and 5,985 (95.8%) received neuraxial ANE. Median time from delivery to LMWH initiation was 15 hours (IQR 12-21) post-cesarean and 14 hours (IQR 11-20) post-vaginal delivery. Time from neuraxial placement and removal to LMWH initiation after cesarean was 21 hours (IQR 14-29) and 13 hours (IQR 9-17), respectively, and after vaginal was 24 hours (IQR 17-30) and 12 hours (IQR 8-18), respectively. Overall, 1,177 (16%) were OB guideline adherent, 4,816 (81%) ANE guideline adherent, and 739 (10%) both OB and ANE adherent. OB guideline adherence was associated with decreased readmission and wound complications, but no difference in VTE or reoperation (Table). ANE guideline or combined guideline adherence was not associated with any outcomes.

Conclusion: Adherence to OB and ANE guidelines for timing of postpartum pharmacologic prophylaxis was low. OB guideline adherence was associated with lower complications.