Rivaroxaban vs Enoxaparin After Cesarean Section: Laboratory Thromboprophylaxis Outcomes

Overview

Pregnancy and the postpartum period increase venous thromboembolism (VTE) risk. After cesarean section, low-molecular-weight heparin (LMWH; enoxaparin) is commonly used for short-term thromboprophylaxis, but it requires daily subcutaneous injections and can cause adverse effects. Direct oral anticoagulants (DOACs) such as rivaroxaban offer convenient once-daily oral dosing. In women who meet institutional criteria for short-term postpartum thromboprophylaxis until hospital discharge, we will compare the laboratory anticoagulant effect of rivaroxaban versus enoxaparin using thrombin generation parameters. This randomized, open-label trial will enroll women undergoing elective cesarean section who are indicated for in-hospital prophylaxis. Blood will be drawn on postoperative day 2 at trough (pre-dose) and peak (\~3 hours post-dose) to measure thrombin generation, anti-Xa activity and drug levels, and participants will complete the Anti-Clot Treatment Scale (ACTS) satisfaction questionnaire. Safety follow-up will occur by telephone at 2 days post-discharge and at 6 weeks postpartum.

Randomized (1:1), open-label, parallel-group, single-center study at Wolfson Medical Center. Eligible participants (Hebrew-speaking, age 18-50, elective cesarean, and meeting local VTE prophylaxis criteria) are randomized to rivaroxaban 10 mg PO once daily or enoxaparin 40 mg SC once daily from the day of surgery until discharge (first dose ≥12 h after cesarean and ≥6 h after spinal anesthesia). On POD2 two blood draws are performed: trough pre-dose and peak \~3 h after dosing. Tests: PT, aPTT, anti-Xa with appropriate calibrators, thrombin generation (endogenous thrombin potential \[ETP\], lag time, peak thrombin). ACTS (Anti-Clot Treatment Scale (ACTS) satisfaction questionnaire) is administered before discharge. Safety follow-up calls 2 days after discharge and 6 weeks postpartum for bleeding, VTE, allergic reactions or other AEs.