UCalgary researcher testing effectiveness of Aspirin in preventing postpartum blood clots

Postpartum blood clots are a leading cause of maternal death in Canada. Venous thromboembolism (VTE), which involves the formation of blood clots in the legs or lungs, most commonly occurs within the first six weeks after childbirth, when the risk is highest.

Although physicians have identified risk factors for developing blood clots after giving birth, such as an unplanned C section, preeclampsia, postpartum infection or hemorrhage, the best way to prevent postpartum thrombosis is still largely unknown. 

Dr. Leslie Skeith, MD, an associate professor in the Departments of Medicine, Community Health Sciences, and Oncology at the Cumming School of Medicine, says that while previous studies have explored the use of injectable blood thinners to prevent postpartum blood clots, research was limited and daily at-home injections proved unpopular among patients.

“Further research is needed,” says Skeith.

Over the past few years, Skeith and her international research team have made strides in solving this problem with the Postpartum Aspirin to Reduce Thromboembolism Undue Morbidity (PARTUM) Trial. 

Their first step was a pilot feasibility trial. The pilot trial looked at the feasibility of a larger trial using low-dose Aspirin (ASA) versus a placebo to prevent postpartum women from developing blood clots. The results, published in The Lancet: Haematology, showed that while ASA is a feasible option for preventing blood clots postpartum, a global trial is needed for confirmation. 

Skeith and her team also identified that the widespread use of blood thinner injections was a barrier to the placebo arm of the pilot trial. This led to a change in the larger study design.

Skeith and her team recently received CIHR Patient Oriented Priority funding to support the next phase of their work. Skeith has been a major proponent of patient engagement and early patient involvement in trial design. She and her team also published a qualitative study about patient perspectives with the pilot trial. 

“We are excited to be kicking off the larger PARTUM trial, which is a non-inferiority trial comparing the use of aspirin with usual care injectable blood thinners,” says Skeith, principal investigator of PARTUM.

The study will begin later this year at three Canadian sites, but the intention is to expand the trial to 11 countries and involve more than 8,000 pregnant patients. Study participants will receive either 81 mg of ASA or be provided with the usual care of blood thinner injections. 

Skeith is hopeful Aspirin will provide a simple intervention for individuals at risk of developing thrombosis after giving birth.

“Aspirin is convenient and affordable, and it is used to prevent blood clots in other areas of medicine, such as after orthopedic surgery,” says Skeith. “This could be a simple way to impact thousands around the world.” 

The PARTUM trial is a global collaboration between researchers and health-care professionals in several disciplines, including hematology, obstetrics, obstetric internal medicine and nursing, as well as patient representatives. Learn more here. 

Dr. Leslie Skeith, MD, is an associate professor in the departments of Medicine, Community Health Sciences and Oncology at the Cumming School of Medicine. She is also a member of the CSM’s Libin Cardiovascular Institute, O’Brien Institute for Public Health and the Alberta Children’s Hospital Research Institute.