Just a few days in simulated microgravity can subtly change the way women’s blood clots, sparking bigger questions about health monitoring protocols for astronauts who can spend six months or more in orbit, say Simon Fraser University researchers. First reported in 2020, an International Space Station mission detected an unexpected blood clot in a female astronaut’s jugular vein. To date, space-health research has had more male participants, but with the number of female astronauts on the rise, a new SFU–European Space Agency study examined how microgravity affects blood clotting specifically in women.