A Phase 3 interventional study of Aspirin and Low-molecular-weight heparin in Venous Thromboembolism, Postpartum Period and Aspirin, sponsored by University of Calgary. Recruiting at 12 sites in 7 countries. Open to female participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-07-27.
Sponsored by University of Calgary · Phase 3, Interventional, and Prevention
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.
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.
712 studies on the registry are indexed under Venous Thromboembolism; 146 are open to participants now.
This study's planned enrollment of 8,805 is above the median of 240 across 401 interventional studies indexed under Venous Thromboembolism.
Browse Venous Thromboembolism studies →University of Calgary is the lead sponsor of 703 studies on the registry; 196 are open to participants now.
Of its 10 completed or terminated interventional studies of FDA-regulated products, 2 (20%) have results posted.
Counted across the registry records on this site, refreshed daily.
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.
ONE (or more) First Order Criterion:
Known inherited thrombophilia diagnosed prior to enrolment, regardless of family history of VTE:
i. Heterozygous factor V Leiden, or ii. Heterozygous prothrombin gene variant, or iii. Protein C deficiency, or iv. Protein S deficiency, and/or
TWO (or more) Second Order Criteria:
Exclusion Criteria:
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:
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.
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
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.
TIA (transient ischaemic attack)
A “mini-stroke”: temporary stroke-like symptoms caused by reduced blood flow to part of the brain, spinal cord or eye, without signs of a new stroke on a scan.
Stroke symptoms need emergency care at once, even if they go away.
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.
Low-dose aspirin (75-100 mg) once daily for 6 weeks.
Drug: Aspirin
Site-specific low-molecular-weight heparin regimen as prescribed by the treating physician.
Drug: Low-molecular-weight heparin
75-100 mg taken once daily by mouth.
Low-molecular-weight heparin injections daily as prescribed by the treating physician.
Also known as: Dalteparin, Enoxaparin, Nadroparin, Tinzaparin
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
Time frame: 6 weeks
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
Time frame: 90 days
Superficial vein thrombosis
A non-compressible vein segment on ultrasound that involves the superficial veins in the lower or upper extremity
Time frame: 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
Time frame: At 6 weeks and at 90 days
Single subsegmental pulmonary embolism (SSPE)
Intraluminal filling defect that involves one subsegmental artery only
Time frame: At 6 weeks and at 90 days
Major bleeding
Based on the ISTH definition
Time frame: At 6 weeks and at 90 days
Clinically relevant non-major bleeding
Based on the ISTH definition
Time frame: At 6 weeks and at 90 days
Wound hematoma requiring intervention
Requiring intervention such as hematoma evacuation or wound packing
Time frame: At 6 weeks and at 90 days
Symptomatic arterial thromboembolism
Ischemic stroke/transient ischemic attack, myocardial infarction, or peripheral arterial embolism
Time frame: At 6 weeks and at 90 days
Postpartum preeclampsia
New preeclampsia presenting in the postpartum period
Time frame: At 6 weeks and at 90 days
Heparin-induced thrombocytopenia
According to a priori categories of definite or possible HIT.
Time frame: At 6 weeks and at 90 days
All-cause mortality
Time frame: At 6 weeks and at 90 days
Plan to share: Yes — Data will be shared upon request.
No publications or documents are linked to this record.
Started Jun 2026 (actual). Primary completion is estimated for Sep 2030, 51 months after the start.
Of 47 phase 3 interventional studies under Venous Thromboembolism, half reached primary completion within 41 months of starting (the median), counting those still running; a quarter within 24 and three quarters within 60. This study's planned 51 months is above that.
How these figures are worked out, and which studies are left out of them.
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Studies of the drug tested here: Aspirin