Venous ThromboembolismPhase 3NCT06494878
The PARTUM Trial: Postpartum Aspirin to Reduce Thromboembolism Undue Morbidity
A Phase 3 study testing Aspirin and Low-molecular-weight heparin in people with Venous Thromboembolism and Postpartum Period, run by University of Calgary at 12 sites in 7 countries.
Trial summary
The goal of the PARTUM trial is to determine if taking low-dose aspirin daily for 6 weeks after delivery is similar (non-inferior) to usual care low-molecular-weight heparin injections to prevent venous thromboembolism (VTE: blood clots in the legs or lungs) for postpartum individuals with VTE risk factors. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Venous Thromboembolism, Postpartum Period, Aspirin
- What is being tested?
- Aspirin and Low-molecular-weight heparin
- Type of treatment
- Pill or oral medicine, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 8,805 participants
- Where
- 12 sitesin 7 countries
- Study dates
- 4 Jun 2026to Dec 2030
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- ONE (or more) First Order Criterion:
- Known inherited thrombophilia diagnosed prior to enrolment, regardless of family history of VTE:
- Heterozygous factor V Leiden, or ii. Heterozygous prothrombin gene variant, or iii. Protein C deficiency, or iv. Protein S deficiency, and/or
- Antepartum immobilization for ≥7 days. Immobilization is defined as bed rest with 90% of waking hours spent in bed at any time during the antepartum period AND/OR
- TWO (or more) Second Order Criteria:
- Pre-pregnancy BMI ≥30 kg/m²
Show all 14Show fewer
- Smoking in the current pregnancy or within 3 months prior to pregnancy
- Previous clinical history of superficial vein thrombosis
- Preeclampsia
- Current pregnancy ending in stillbirth (pregnancy loss >20 weeks gestation)
- Unplanned cesarean delivery (unplanned = not a scheduled cesarean delivery)
- Small-for-gestational-age infant at time of delivery (<3rd percentile adjusted for gestational age and sex)
- Peripartum or postpartum infection (symptoms/signs of infection and documented fever and laboratory evidence of infection with positive blood cultures or an elevated white blood cell count based on local laboratory cutoffs)
- Postpartum hemorrhage (≥1000 mL of blood loss, regardless of delivery mode)
Who cannot join
- More than 48 hours since delivery at the time of randomization
- Received more than 1 dose of LMWH since delivery
- Need for postpartum LMWH prophylaxis or systemic anticoagulation as judged by their physician and/or local investigator. May include but is not limited to:
- Documented history of provoked or unprovoked VTE
- Mechanical heart valve(s)
- Known antiphospholipid syndrome (APS)
Show all 14Show fewer
- Known high-risk inherited thrombophilia i) Antithrombin deficiency, or ii) Homozygous factor V Leiden, or iii) Homozygous prothrombin gene mutation, or iv) More than 1 thrombophilia: any combination of 2 or more: factor V Leiden, prothrombin gene mutation, protein C deficiency, protein S deficiency
- Need for postpartum ASA as judged by their physician and/or local investigator. May include but is not limited to:
- Documented history of myocardial infarction
- Documented history of ischemic stroke or transient ischemic attack (TIA)
- Active bleeding, excluding normal vaginal bleeding, at the time of randomization
- Known medical condition as judged by their physician and/or local investigator to be a contraindication to ASA or LMWH including known ASA or LMWH allergy
- <18 years of age
- Unable or declined consent
Trial locations and contacts
12 sites in 7 countries. Contact the study team or a site near you to ask about taking part.
12 sites in 7 countries
France4 sites, 4 recruiting
- Not yet recruiting
CHU de Nancy
Nancy, 54000
Olivier Morel, MD, PhD, +33(0)3 83 34 42 12, o.morel@chrunancy.fr
Olivier Morel, MD, PhD
- Not yet recruiting
APHP - Hôpital Port Royal
Paris, 75014
Aude Girault, MD, PhD, +33(0)6 88 21 39 92, aude.girault@aphp.fr
Aude Girault, MD, PhD
- Not yet recruiting
CHU de Saint-Etienne
Saint-Etienne, 42055
Tiphaine Barjat, MD, PhD, +33 (0)4 77 82 86 09, Tiphaine.barjat@chu-st-etienne.fr
Bernard Tardy, MD, PhD, +33(0)4 77 12 77 88, bernard.tardy2@chu-st-etienne.fr
- Not yet recruiting
CHU de Toulouse
Toulouse, 31059
Paul Guerby, MD, PhD, +33(0)5 67 77 11 06, guerby.p@chutoulouse.fr
Paul Guerby, MD, PhD
Canada2 sites, 2 recruiting
- Recruiting
Foothills Medical Centre
Calgary, Alberta, T2N 2T9
Leslie Skeith, MD, 403-944-5246, laskeith@ucalgary.ca
Jill Baxter, BSc Kin, 403-220-7103, jbaxter@ucalgary.ca
- Not yet recruiting
The Ottawa Hospital - General Campus
Ottawa, Ontario, K1H 8L6
Darine El-Chaar, MD, 613-737-8797, delchaar@toh.ca
Ireland2 sites, 2 recruiting
- Not yet recruiting
Rotunda Hospital, RCSI Department of Obstetrics and Gynaecology
Dublin, D01 P5W9
Jennifer Donnelly, Consultant Obstetrician/MFM, MD, 0876497966, jdonnelly@rotunda.ie
Zara Molphy, Head of Research Programs, zmolphy@rcsi.ie
- Not yet recruiting
UCD Centre for Human Reproduction, The Coombe Hospital
Dublin, D08XW7X
Amy O'Higgins, Associate Professor of Obstetrics & Gynaecology, +353 1 4085200 ext. 4887, amy.ohiggins@ucd.ie
Massimo Ruben, UCD Research Manager, massimo.ruben@ucd.ie
Belgium1 site, 1 recruiting
- Not yet recruiting
Association Hospitalière De Bruxelles Et De Schaerbeek - Centre Hospitalier Universitaire Brugmann
Brussels, 1020
Jacques Jani, MD, PhD, 0032 2 4772930, JACQUES.JANI@chu-brugmann.be
Jeanne-Irène Tchapda, 0032 2 4773310, jeanneirene.tchapda@chu-brugmann.be
Denmark1 site, 1 recruiting
- Not yet recruiting
Hvidovre Hospital
Hvidovre, Capital Region, 2650
Charlotte Holm Bischof, MD, PhD, +4527200832, charlotte.holm.04@regionh.dk
Jens Fuglsang, MD, PhD, fuglsang@clin.au.dk
Netherlands1 site, 1 recruiting
- Not yet recruiting
Amsterdam UMC
Amsterdam, 1105AZ
Marjon A de Boer, MD, PhD, +31-627243773, m.deboer2@amsterdamumc.nl
Marjolijn Blits, +316-50 06 38 16, onderzoeksbureauvkc@amsterdamumc.nl
Poland1 site, 1 recruiting
- Not yet recruiting
Medical University of Warsaw
Warsaw, 02-091
Piotr Pruszczyk, +48/225021144, piotr.pruszczyk@wum.edu.pl
Michal Ciurzynski, 48/22/5021144, michal.ciurzynski@wum.edu.pl
About this study
Official title: The PARTUM (Postpartum Aspirin to Reduce Thromboembolism Undue Morbidity) Trial
The goal of the PARTUM trial is to determine if taking low-dose aspirin daily for 6 weeks after delivery is similar (non-inferior) to usual care low-molecular-weight heparin injections to prevent venous thromboembolism (VTE: blood clots in the legs or lungs) for postpartum individuals with VTE risk factors.
Read the detailed description
The PARTUM trial design is a Prospective Randomized Open Blinded End-point (PROBE) non-inferiority trial. Participants with risk factors for venous thromboembolism (VTE) as defined by the inclusion criteria will be identified during pregnancy, labor and delivery, and up to 48 hours after delivery.
Eligible and consenting participants will be randomly assigned to one of two study arms: Low-dose aspirin (75-100mg according to country availability) daily for 42 days post-randomization, or a usual care site-specific low-molecular-weight-heparin (LMWH) regimen with the dose and duration of LMWH determined by the participant's healthcare provider.
Follow-up will occur at 6 weeks and 90 days post-randomization.
- Being tested
- Aspirin, Low-molecular-weight heparin
- Keywords
- deep vein thrombosis, pulmonary embolism, postpartum, pregnancy, thrombophilia, cesarean delivery, preeclampsia, small-for-gestational age infant, postpartum hemorrhage, postpartum infection
- Medical subject headings
- Venous Thromboembolism, Venous Thrombosis, Pulmonary Embolism, Thrombophilia, Pre-Eclampsia, Postpartum Hemorrhage
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AspirinDrug
75-100 mg taken once daily by mouth.
Low-molecular-weight heparinDrug
Also called Dalteparin, Enoxaparin, Nadroparin, Tinzaparin
Low-molecular-weight heparin injections daily as prescribed by the treating physician.
| Study group | Role | What they receive |
|---|---|---|
| Aspirin | Experimental | Low-dose aspirin (75-100 mg) once daily for 6 weeks. Receives: Drug: Aspirin |
| Low-molecular-weight heparin | Active comparator | Site-specific low-molecular-weight heparin regimen as prescribed by the treating physician. Receives: Drug: Low-molecular-weight heparin |
What is being measured
The primary outcome is the main question the study is designed to answer.
Symptomatic VTE
Proximal lower or upper extremity DVT, PE involving segmental or higher arteries or multiple subsegmental arteries, and unusual site [non-limb] venous thromboembolism
Measured: 6 weeks
Secondary outcomes (11)
Late symptomatic VTE
Proximal lower or upper extremity DVT, PE involving segmental or higher arteries or multiple subsegmental arteries, and unusual site [non-limb] venous thromboembolism
Measured: 90 days
Superficial vein thrombosis
A non-compressible vein segment on ultrasound that involves the superficial veins in the lower or upper extremity
Measured: At 6 weeks and at 90 days
Distal deep vein thrombosis
A non-compressible vein segment on ultrasound involving the deep veins that is distal to the popliteal vein in the lower extremity, or distal to the axillary vein in the upper extremity
Measured: At 6 weeks and at 90 days
Single subsegmental pulmonary embolism (SSPE)
Intraluminal filling defect that involves one subsegmental artery only
Measured: At 6 weeks and at 90 days
Major bleeding
Based on the ISTH definition
Measured: At 6 weeks and at 90 days
Clinically relevant non-major bleeding
Based on the ISTH definition
Measured: At 6 weeks and at 90 days
Wound hematoma requiring intervention
Requiring intervention such as hematoma evacuation or wound packing
Measured: At 6 weeks and at 90 days
Symptomatic arterial thromboembolism
Ischemic stroke/transient ischemic attack, myocardial infarction, or peripheral arterial embolism
Measured: At 6 weeks and at 90 days
Postpartum preeclampsia
New preeclampsia presenting in the postpartum period
Measured: At 6 weeks and at 90 days
Heparin-induced thrombocytopenia
According to a priori categories of definite or possible HIT.
Measured: At 6 weeks and at 90 days
All-cause mortality
Measured: At 6 weeks and at 90 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Jul 2024
- Study start4 Jun 2026
- Primary completionSep 2030 (estimated)
- Study completionDec 2030 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Venous ThromboembolismStudies of the same condition, open and under way.
- More trials run by University of CalgaryThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 8,805 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Calgary
- Sponsor type
- University, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR), European Clinical Research Infrastructure Network
- Responsible party
- Sponsor
- Investigators
- Leslie Skeith, MD, Principal investigator, University of CalgaryMarc Rodger, MD, Principal investigator, McGill University Health Centre/Research Institute of the McGill University Health Centre
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06494878
- Sponsor's protocol ID
- REB24-0317
- Status last verified
- Jun 2026
- First submitted
- 12 Jun 2024
- Last updated
- 27 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data will be shared upon request.
Study at a glance
From the registry record, last updated by the sponsor on 27 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The PARTUM (Postpartum Aspirin to Reduce Thromboembolism Undue Morbidity) Trial
- ClinicalTrials.gov ID
- NCT06494878
- Acronym / sponsor ID
- REB24-0317
- Keywords
- deep vein thrombosis, pulmonary embolism, postpartum, pregnancy, thrombophilia, cesarean delivery, preeclampsia, small-for-gestational age infant
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 8,805 participants (estimated)
- Lead sponsor
- University of CalgaryUniversity, hospital or other
- Collaborators
- Canadian Institutes of Health Research (CIHR), European Clinical Research Infrastructure Network
- Study start
- 4 Jun 2026 (actual)
- Primary completion
- Sep 2030 (estimated)
- Study completion
- Dec 2030 (estimated)
- First posted
- 10 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of the PARTUM trial is to determine if taking low-dose aspirin daily for 6 weeks after delivery is similar (non-inferior) to usual care low-molecular-weight heparin injections to prevent venous thromboembolism (VTE: blood clots in the legs or lungs) for postpartum individuals with VTE risk factors.
Detailed description
The PARTUM trial design is a Prospective Randomized Open Blinded End-point (PROBE) non-inferiority trial. Participants with risk factors for venous thromboembolism (VTE) as defined by the inclusion criteria will be identified during pregnancy, labor and delivery, and up to 48 hours after delivery.
Eligible and consenting participants will be randomly assigned to one of two study arms: Low-dose aspirin (75-100mg according to country availability) daily for 42 days post-randomization, or a usual care site-specific low-molecular-weight-heparin (LMWH) regimen with the dose and duration of LMWH determined by the participant's healthcare provider.
Follow-up will occur at 6 weeks and 90 days post-randomization.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Aspirin | Experimental | Drug: AspirinLow-dose aspirin (75-100 mg) once daily for 6 weeks. |
| Low-molecular-weight heparin | Active comparator | Drug: Low-molecular-weight heparinSite-specific low-molecular-weight heparin regimen as prescribed by the treating physician. |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (14 listed)
- ONE (or more) First Order Criterion:
- Pre-pregnancy BMI ≥30 kg/m²
- Smoking in the current pregnancy or within 3 months prior to pregnancy
- Previous clinical history of superficial vein thrombosis
- Preeclampsia
Key exclusion criteria (14 listed)
- More than 48 hours since delivery at the time of randomization
- Received more than 1 dose of LMWH since delivery
- Need for postpartum LMWH prophylaxis or systemic anticoagulation as judged by their physician and/or local investigator. May include but is not limited to:
- Need for postpartum ASA as judged by their physician and/or local investigator. May include but is not limited to:
- Active bleeding, excluding normal vaginal bleeding, at the time of randomization
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Aspirin75-100 mg taken once daily by mouth. | Drug | Aspirin |
| Low-molecular-weight heparinAlso: Dalteparin, Enoxaparin, Nadroparin, TinzaparinLow-molecular-weight heparin injections daily as prescribed by the treating physician. | Drug | Low-molecular-weight heparin |
Primary outcome
Symptomatic VTE
Time frame: 6 weeks
Proximal lower or upper extremity DVT, PE involving segmental or higher arteries or multiple subsegmental arteries, and unusual site [non-limb] venous thromboembolism
11 secondary outcomes
Late symptomatic VTE
Time frame: 90 days
Superficial vein thrombosis
Time frame: At 6 weeks and at 90 days
Distal deep vein thrombosis
Time frame: At 6 weeks and at 90 days
Single subsegmental pulmonary embolism (SSPE)
Time frame: At 6 weeks and at 90 days
Major bleeding
Time frame: At 6 weeks and at 90 days
Clinically relevant non-major bleeding
Time frame: At 6 weeks and at 90 days
Wound hematoma requiring intervention
Time frame: At 6 weeks and at 90 days
Symptomatic arterial thromboembolism
Time frame: At 6 weeks and at 90 days
Postpartum preeclampsia
Time frame: At 6 weeks and at 90 days
Heparin-induced thrombocytopenia
Time frame: At 6 weeks and at 90 days
All-cause mortality
Time frame: At 6 weeks and at 90 days
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 27 Jul 2026.
- Individual participant dataSharing planned: Yes. Data will be shared upon request.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Leslie Skeith, MD principal investigator
University of Calgary
Marc Rodger, MD principal investigator
McGill University Health Centre/Research Institute of the McGill University Health Centre
12 sites in 7 countries: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing Aspirin and Low-molecular-weight heparin in people with Venous Thromboembolism and Postpartum Period, run by University of Calgary at 12 sites in 7 countries.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 14 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 27 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 12 sites in France, Canada, Ireland, Belgium, Denmark and 2 more countries. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Leslie Skeith, MD (403-944-5246, laskeith@ucalgary.ca), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Symptomatic VTE (time frame: 6 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Jul 2026.