An interventional study of Rivaroxaban and Enoxaparin 40 mg in Postpartum Period, Cesarean Section Surgery and VTE (Venous Thromboembolism), sponsored by Wolfson Medical Center. Recruiting at 1 site in Israel. Open to female participants aged 18 Years to 50 Years. Per ClinicalTrials.gov, last updated 2026-09-15.
Sponsored by Wolfson Medical Center · Not applicable, Interventional, and Prevention
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.
712 studies on the registry are indexed under Venous Thromboembolism; 146 are open to participants now.
This study's planned enrollment of 62 is below the median of 240 across 401 interventional studies indexed under Venous Thromboembolism.
Browse Venous Thromboembolism studies →Wolfson Medical Center is the lead sponsor of 118 studies on the registry; 17 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Creatinine clearance (CrCl)
How quickly the kidneys clear creatinine, a waste product, from the blood. A study may estimate it from a blood test with age, weight and sex (often by the Cockcroft–Gault formula), or measure it using blood and urine collected over a set time. Given in mL/min; higher is better.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Bilirubin
A yellow substance made when red blood cells are broken down, which the liver clears. A high level can mean a problem with the liver or the bile ducts.
Criteria often allow more for people with Gilbert’s syndrome, a harmless inherited condition that raises bilirubin.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
CYP3A (CYP3A4) inhibitors and inducers
CYP3A is a group of enzymes, mainly CYP3A4, in the liver and gut that break down many medicines. Some medicines, supplements and foods (grapefruit, St John’s wort) slow them down or speed them up, which changes how much of a study drug stays in the body.
Studies list them so they can be avoided or switched; bring a list of everything you take, including supplements.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receive rivaroxaban 10 mg orally (PO) once daily, starting ≥12 hours after cesarean delivery and ≥6 hours after spinal anesthesia, and continuing once daily during the index hospitalization until discharge. Standard postpartum care is provided to all participants.
Drug: Rivaroxaban
Participants receive enoxaparin 40 mg subcutaneously (SC) once daily, starting ≥12 hours after cesarean delivery and ≥6 hours after spinal anesthesia, and continuing once daily during the index hospitalization until discharge. Standard postpartum care is provided to all participants
Drug: Enoxaparin 40 mg
10 mg PO once daily from ≥12 h post-C-section until discharge
Also known as: Xarelto
40 mg SC once daily from ≥12 h post-C-section until discharge
Also known as: Clexane
Endogenous Thrombin Potential (ETP)
Between-group comparison of ETP to assess similarity of anticoagulant effect; lower ETP indicates greater anticoagulation.
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)
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 - Peak Thrombin (nM)
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
Anti-Xa activity (IU/mL) - Enoxaparin arm
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
Plasma Rivaroxaban Concentration (ng/mL) - Rivaroxaban arm
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
Treatment Satisfaction (ACTS Questionnaire total and subscales)
The Anti-Clot Treatment Scale (validated patient-reported measure; higher scores reflect greater satisfaction)
Time frame: Postoperative day 2, prior to hospital discharge
Adverse Events (bleeding and VTE)
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.
Time frame: From randomization through 6 weeks postpartum, including assessment during the index hospitalization, approximately 2 days after discharge, and at 6 weeks postpartum
Plan to share: Yes — De-identified individual participant data (IPD) underlying the main results will be shared, including: demographics and baseline characteristics; operative/anesthesia details relevant to timing; thrombin-generation parameters (ETP, lag time, peak thrombin); anti-Xa activity (enoxaparin arm); plasma rivaroxaban levels (rivaroxaban arm); ACTS questionnaire scores; adverse events (bleeding/VTE) and follow-up outcomes through 6 weeks postpartum. A data dictionary/codebook will accompany the dataset. Free-text notes and direct identifiers (names, full dates, contact details, MRNs) will not be shared.
Supporting information: Study protocol, Statistical analysis plan, Informed consent form, Analytic code
Time frame: Data and supporting documents will be available starting 6 months after publication of the primary results (or 12 months after primary completion, whichever occurs first) and will remain available for 5 years thereafter.
Access criteria: Qualified researchers affiliated with academic or healthcare institutions may request access by emailing the Principal Investigator (contact listed in this record) with a brief proposal (objectives, methods, variables requested, analysis plan) and documentation of local IRB/ethics approval or exemption. Requests will be reviewed within \~30 days by the study investigators for methodological soundness and consistency with participant consent. Approved requestors must sign a Data Use Agreement (DUA) specifying: use only for the approved purpose; no re-identification or contact of participants; no onward sharing; secure data storage; prompt reporting of breaches; and publication transparency (cite this study and share analytic code upon publication). Data will be transferred via secure encrypted file exchange (or read-only secure environment) after DUA execution.
Started Dec 2025 (actual). Primary completion is estimated for Jun 2027, 18 months after the start.
Of 65 non-industry interventional studies with no phase under Venous Thromboembolism, half reached primary completion within 31 months of starting (the median), counting those still running; a quarter within 19 and three quarters within 57. This study's planned 18 months is below that.
Counting every sponsor, half of 70 studies reached it within 31 months; a quarter within 19 and three quarters within 57.
How these figures are worked out, and which studies are left out of them.
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Studies of the drug tested here: Rivaroxaban