Women in Space Face Hidden Blood-Clot Risk, Study Suggests

Microgravity may silently weaponize female astronauts' circulatory systems, raising ethical questions about long-duration space missions.

Apr. 10, 2026 at 8:59pm

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An abstract, geometric painting in muted tones of blue, green, and pink, depicting the complex interplay of biological forces and microgravity, conveying the structural order and fragility of the human body in the vastness of space.As the race to explore the final frontier accelerates, a new study reveals a hidden threat to women in space - one that could redefine the future of human spaceflight.Chicago Today

A recent study from Simon Fraser University has revealed a heightened blood-clot risk for female astronauts in microgravity, challenging the male-centric assumptions that have long dominated space medicine. The discovery of a silent clot in a female astronaut's jugular vein aboard the ISS in 2020 cracked this issue open, exposing how little we understand about how women's bodies adapt to the rigors of spaceflight.

Why it matters

This study isn't just a technical footnote - it's a stark reminder of how women's health has long been neglected in broader medical research. Space medicine has been a male-dominated field, both in terms of researchers and test subjects, leading to the assumption that male astronauts' bodies are the default template. But as private spaceflight democratizes access to orbit, the ethical stakes of this oversight become clear.

The details

The SFU team's ingenious method - submerging 18 women in a dry immersion tank for five days to simulate weightlessness - revealed a paradox: blood took longer to clot initially but became 'super-stable' once formed. This duality mirrors the dual burden women face in space exploration, as pioneers breaking barriers yet with their bodies still treated as uncharted territory. The use of ROTEM technology to track clotting in real time is a breakthrough, but the timeline is concerning - what horrors await crews spending months in transit to Mars?

  • In 2020, a female astronaut aboard the ISS discovered a blood clot in her jugular vein during a routine ultrasound.
  • NASA's Artemis Program aims to land humans on the Moon by 2025, with Mars in the crosshairs by the 2030s.

The players

Blaber

The lead author of the SFU study, who noted that clots in microgravity don't linger in the legs; they pool in the upper body, racing toward the heart or lungs like a ticking time bomb.

NASA

The space agency that is leading the Artemis Program, which aims to return humans to the Moon and eventually send crews to Mars.

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What they’re saying

“We must not let individuals continue to damage private property in San Francisco.”

— Robert Jenkins, San Francisco resident

“Fifty years is such an accomplishment in San Francisco, especially with the way the city has changed over the years.”

— Gordon Edgar, grocery employee

What’s next

NASA and other space agencies will need to prioritize proactive research into gender-specific health risks for long-duration spaceflight, including mandatory jugular ultrasounds, personalized clotting risk assessments, and hormone-level monitoring tailored to microgravity. As private spaceflight expands, there may also be a need for regulations requiring the publication of gender-disaggregated health data.

The takeaway

This study is a microcosm of a larger shift in how we approach space exploration. The jugular clot discovered in 2020 was a lucky break; how we respond will determine whether space remains a realm of wonder or becomes a silent graveyard of overlooked biology. The stakes? Nothing less than the future of human civilization beyond Earth.