Postpartum pharmacologic thromboprophylaxis guideline adherence and post-delivery complications: a single-center retrospective cohort study

OBJECTIVE: Obstetric and anesthesia guidelines provide differing recommendations for the timing of initiation of postpartum pharmacologic thromboprophylaxis relative to delivery time, mode of delivery, and anesthesia type and administration time. We aimed to (1) describe the rate of adherence to obstetric (OB) and anesthesia (ANE) guidelines for timing of postpartum pharmacologic thromboprophylaxis initiation, (2) assess trends in adherence over time, and (3) 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. The primary outcome was guideline adherence. 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, readmission, reoperation, and wound complications within six weeks postpartum. Rate of adherence to guidelines and trends in adherence were assessed. Multivariable models estimated the association between guideline adherence and secondary outcomes. RESULTS: Of 5,959 included, 3,952 (66.3%) underwent cesarean delivery. Overall, 926 (15.5%) were OB guideline adherent, 4,800 (80.6%) ANE guideline adherent, and 488 (8.2%) both OB and ANE adherent. Guideline adherence increased over time (p<0.001 for trend). OB guideline adherence was associated with decreased readmission among those undergoing cesarean delivery, but no difference in VTE, reoperation, or wound complications. ANE guideline or combined guideline adherence was not associated with any outcomes. CONCLUSION: Adherence to OB guidelines for timing of postpartum pharmacologic prophylaxis was low, while adherence to ANE guidelines was much higher. OB, ANE, or both guideline adherence was not associated with lower rates of VTE or complications.