Pilot PARTUM Trial: Postpartum Aspirin to Reduce Thromboembolism Undue Morbidity

  • End date
    Dec 26, 2021
  • participants needed
  • sponsor
    University of Calgary
Updated on 26 January 2021
protein c
factor v leiden


The pilot PARTUM trial is a randomized, multicenter, placebo-controlled trial. Women who are at modest risk of VTE (as defined by the inclusion criteria) will be identified during pregnancy, labor and delivery and up to 48 hours postpartum. Eligible and consenting participants will be randomly assigned to one of two study arms: aspirin 81 mg daily or placebo daily for 6 weeks.


The purpose of the pilot PARTUM trial is to determine whether it is feasible to conduct a larger randomized controlled trial to determine whether low-dose aspirin is efficacious and safe at preventing postpartum venous thromboembolism (VTE) in women at increased risk of VTE, compared to placebo.

Given the large sample size needed to adequately power a large multicenter trial that assesses the efficacy of aspirin 81 mg versus placebo, the investigators first need to determine if it is possible to recruit enough women. If the pilot trial is successful and there are no major changes to the study design, then the secondary clinical outcomes collected in the pilot trial will be used in the analysis of the full multicenter trial.

Condition Venous Thromboembolism, Postpartum, Thromboembolism, Aspirin, acetylsalicylic acid
Treatment Placebo, Aspirin 81 mg
Clinical Study IdentifierNCT04153760
SponsorUniversity of Calgary
Last Modified on26 January 2021


Yes No Not Sure

Inclusion Criteria

Is your age greater than or equal to 18 yrs?
Are you female?
Do you have any of these conditions: Venous Thromboembolism or Thromboembolism or Aspirin or Postpartum?
Do you have any of these conditions: Aspirin or Venous Thromboembolism or acetylsalicylic acid or Postpartum or Thromboembolism?
Study inclusion criteria includes one (or more) first
order criterion or two (or more) second order criteria. A patient is still
eligible if they have multiple criteria met, at the discretion of the local
ONE (or more) First Order Criteria
Known inherited thrombophilia diagnosed prior to enrolment
Heterozygous factor V Leiden, OR ii) Heterozygous prothrombin gene variant, OR iii) Protein C deficiency, OR iv) Protein S deficiency
Immobilization (90% of waking hours spent in bed) for 7 days anytime during the antepartum period
TWO (or more) Second Order Criteria
Postpartum infection
Postpartum hemorrhage (>1000 mL of blood loss, regardless of delivery mode)
Pre-pregnancy BMI 30 kg/m2
Emergency or unplanned cesarean delivery
Smoking 5 cigarettes/day before pregnancy
Current pregnancy ending in stillbirth (pregnancy loss >20 weeks gestation)
Small-for-gestational-age infant (<3rd percentile adjusted for gestational age and sex)
Previous history of superficial vein thrombosis

Exclusion Criteria

More than 48 hours since delivery
Received more than 2 doses of low-molecular-weight heparin (LMWH) since delivery
Need for postpartum LMWH prophylaxis or systemic anticoagulation as judged by the local investigator. May include but is not limited to
Documented history of provoked or unprovoked VTE
Mechanical heart valve(s)
Known antiphospholipid syndrome
Known high-risk inherited thrombophilia i) Antithrombin deficiency; ii) Homozygous factor V Leiden; iii) Homozygous prothrombin gene mutation; iv) Compound heterozygosity factor V Leiden and prothrombin gene mutation; v) More than one inherited thrombophilia
Need for postpartum aspirin as judged by the local investigator. May include but is not limited to
Documented history of myocardial infarction
Documented history of ischemic stroke or transient ischemic attack (TIA)
Contraindication to aspirin including
History of known aspirin allergy
Documented history of a gastrointestinal ulcer
Known platelet count <50 x 109/L at any time during the current pregnancy or postpartum
Active bleeding at any site, excluding normal vaginal bleeding, at the time of randomization
Most recent known hemoglobin 70 g/L documented during the current pregnancy or postpartum
Known severe hypertension (SBP >200mm/hg and/or DBP >120mm/hg) during the current pregnancy or postpartum
<18 years of age
Unable or refused consent
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