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NCT Number: NCT07820670

Rivaroxaban vs Enoxaparin After Cesarean Section: Laboratory Thromboprophylaxis Outcomes

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.

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Key information

Conditions

Postpartum Period Cardiovascular Diseases Cesarean Section Surgery Embolism and Thrombosis Thromboembolism VTE (Venous Thromboembolism) Vascular Diseases Venous Thromboembolism

Age range

18 year–50 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Edith Wolfson Medical Center

Holon, 6997107, Israel

Location status: Recruiting

Location contact

Hagit Eisenberg, MD

CONTACT

[email protected]

+972523397843

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Hebrew-speaking women
  • age 18-50
  • Elective cesarean at Wolfson
  • Indicated for in-hospital thromboprophylaxis per local protocol (need ≥2 risk factors among: cesarean delivery; age >35; BMI >30; parity ≥3; labor duration ≥12 h; postpartum hemorrhage or blood transfusion; reduced mobility)

Exclusion criteria

  • Known thrombophilia
  • Prior arterial/venous thrombosis
  • Creatinine clearance <29 mL/min
  • Abnormal liver enzymes/bilirubin or liver disease
  • Coagulation disorders
  • Platelets <75,000/mm³
  • Interacting drugs affecting DOAC metabolism (e.g., strong CYP3A4/P-gp modulators; azoles; protease inhibitors; rifampicin; phenytoin; carbamazepine; phenobarbital; St. John's wort; dronedarone)
  • Active bleeding or contraindication to anticoagulation
  • Peptic disease/GI bleeding history
  • Hemoptysis risk/history
  • Preeclampsia
  • Active infection
  • Significant lower-limb varicosities
  • Need for prophylaxis beyond discharge (≥3 risk factors)
  • Maternal weight <50 kg or >100 kg

Treatment and study plan

Rivaroxaban

Drug

10 mg PO once daily from ≥12 h post-C-section until discharge

Other names: Xarelto

Enoxaparin 40 mg

Drug

40 mg SC once daily from ≥12 h post-C-section until discharge

Other names: Clexane

Primary outcomes

  1. Endogenous Thrombin Potential (ETP)

    Time frame: Postoperative day 2: immediately before the study drug dose (trough) and approximately 3 hours after the study drug dose (peak), during the index hospitalization

    Between-group comparison of ETP to assess similarity of anticoagulant effect; lower ETP indicates greater anticoagulation.

Secondary outcomes

  1. Thrombin Generation - Lag Time (minutes)

    Time frame: Postoperative day 2: immediately before the study drug dose (trough) and approximately 3 hours after the study drug dose (peak), during the index hospitalization

    Thrombin Generation - Lag Time (minutes)

  2. Thrombin Generation - Peak Thrombin (nM)

    Time frame: Postoperative day 2: immediately before the study drug dose (trough) and approximately 3 hours after the study drug dose (peak), during the index hospitalization

    Thrombin Generation - Peak Thrombin (nM)

  3. Anti-Xa activity (IU/mL) - Enoxaparin arm

    Time frame: Postoperative day 2: immediately before the enoxaparin dose (trough) and approximately 3 hours after the enoxaparin dose (peak), during the index hospitalization

    Anti-Xa activity (IU/mL) - Enoxaparin arm

  4. Plasma Rivaroxaban Concentration (ng/mL) - Rivaroxaban arm

    Time frame: Postoperative day 2: immediately before the rivaroxaban dose (trough) and approximately 3 hours after the rivaroxaban dose (peak), during the index hospitalization

    Plasma Rivaroxaban Concentration (ng/mL) - Rivaroxaban arm

  5. Treatment Satisfaction (ACTS Questionnaire total and subscales)

    Time frame: Postoperative day 2, prior to hospital discharge

    The Anti-Clot Treatment Scale (validated patient-reported measure; higher scores reflect greater satisfaction)

  6. Adverse Events (bleeding and VTE)

    Time frame: From randomization through 6 weeks postpartum, including assessment during the index hospitalization, approximately 2 days after discharge, and at 6 weeks postpartum

    Clinically evident bleeding, confirmed VTE events, allergic reactions, or other AEs possibly related to study drugs, collected during hospitalization and via phone at ~2 days post-discharge and 6 weeks.

Study contacts

Contact information is provided by the study sponsor or research team.

Hagit Eisenberg, MD

CONTACT

[email protected]

+972-52-3397843

Or Marom, MD

CONTACT

[email protected]

+972-52-554-0490

Sponsors and collaborators

Lead sponsor

Wolfson Medical Center

Other Gov

Registry information

Official study title

The Laboratory Effect of Rivaroxaban Compared to Enoxaparin as Prophylactic Anticoagulant Therapy After Cesarean Section: A Randomized Open-Label Trial

Important dates

Study start
2025
Primary completion
2027
Study completion
2027
First posted
Sep 15, 2026
Registry last updated
Sep 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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