Low-molecular-weight heparin vs aspirin postpartum (LEAP): a single-center pilot randomized control trial

Low-molecular-weight heparin (LMWH) for 6 weeks postpartum for prophylaxis of venous thromboembolism (VTE) is suggested for patients with previous VTE or high-risk thrombophilia, yet evidence supporting this duration is limited. This study assesses the feasibility of a randomized controlled trial (RCT) comparing a shorter duration of LMWH postpartum. In a single-center pilot feasibility study, patients with previous VTE or high-risk thrombophilia were randomized to receive either 6 weeks of LMWH or a 3-week course of LMWH followed by 3 weeks of low-dose aspirin. We evaluated enrollment, adherence rates, and retention. Secondary outcomes included objectively confirmed VTE, bleeding events using the International Society on Thrombosis and Haemostasis criteria, and patient satisfaction via the Perception of Anti-Coagulant Treatment Questionnaire at 3 and 6 weeks postpartum. From October 2021 to July 2023, 67 individuals were screened, yielding a consent rate of 55%, with 30 participants enrolled. Fourteen patients were randomized to the LMWH group and 13 to the LMWH-aspirin group. Adherence was achieved in both groups (96.5% for LMWH, 93.9% for LMWH-aspirin, P = .027). Missing data were minimal. No VTE or maternal deaths occurred. One participant in the LMWH arm had delayed postpartum hemorrhage. Quality of life was improved in the combined treatment group at 6 weeks (P < .001). This single-center pilot study indicates that a larger RCT to evaluate a mixed regimen of LMWH and aspirin against traditional LMWH therapy is feasible. Enrollment and adherence rates were achieved, and quality of life may be improved. This trial was registered at www.ClinicalTrials.gov as #NCT05058924.