Are Periods in Space Different from Earth? How Astronauts Approach Menstruation In Zero G

Things can get pretty weird in space. During his 340 days at the International Space Station, astronaut Scott Kelly grew two inches and aged less, albeit by just a millisecond, than he would have on Earth. And in addition to doing space walks and conducting scientific experiments, Kelly also had to deal with basic bodily functions — which aren't so mundane when you're floating in zero gravity.

NASA talks about space toilets and sponge baths as being part of astronaut's daily routines, but for astronauts who menstruate, what happens during that "time of the month?"

According to the New York Times, there used to be a myth that menstruating in space was unsafe, if not impossible. Scientists used to believe that zero gravity would cause the blood to reverse its usual course and instead accumulate in the abdomen.  

Read more: Scott Kelly Is Heading Back to Earth — Here's What NASA Might Discover

But while, physiologically, having a period works the same way in space as it does on Earth, it can be tricky. For that reason, some women elect to use birth control pills to skip their period altogether, though to do so requires about 1,100 pills for a three-year mission, and what's more, the jury is still out in terms of space's effect on hormonal drugs.

In a study published in Nature on Thursday, authors Varsha Jain and Virginia E. Wotring wrote, "The practicalities of personal hygiene while menstruating during spaceflight could be challenging, e.g., limited wash water supply or the task of changing hygiene products in microgravity. Nonetheless, full amenities are available should astronauts choose to menstruate."

Long-term menstruation suppression devices like IUDs are ideal for reducing waste and weight on space crafts, but Jain and Wotring stated that it's important to give women ownership of their own bodies.

"Offering female astronauts up-to-date, evidence-based, comprehensive education, in view of the environment in which they work, would empower them to make informed decisions regarding menstrual suppression while respecting their autonomy."