What Happens if You Get Your Period in Outer Space?

Thirty-two years ago, a 32-year-old Sally Ride was launched into space, becoming the first American woman to do so.

There was only one problem: What if she got her period?

There are numerous things that go into preparing for a space launch: checking oxygen levels, testing the communications system, signing off on proper meteorological conditions. But until Ride's first flight, sanitary napkins hadn't been part of the checklist.

"When it came to menstruation, the poor engineers just really didn't have a clue," said Lynn Sherr, Sally Ride's biographer, in the documentary MAKERS: Women in Space. Engineers had been preparing for the inclusion of women in space for years—everything from refitting space suits to fit women, to developing different toilet apparatuses to fit the female anatomy—but menstruation posed a unique problem.

The question of zero-gravity menstruation perplexed NASA's medical specialists. What would happen if you had your period in space? Would the blood stay lodged in the uterus, or would it create blobs of free-floating blood? NASA's medics were specifically concerned about the risk of retrograde menstruation, a condition where menstrual fluid travels backwards in the fallopian tubes. Retrograde menstruation is an earthbound condition (it's believed to be the cause of endometriosis), but scientists figured the lack of gravity would increase the likelihood. If gravity pushes menstrual blood out, then a lack of gravity might push it back in.

Rhea Seddon, who was part of the first group of astronauts to include women, remembers these conversations about menstruation among NASA's medical team. In her oral history, Seddon recalls, "We [female astronauts] were asked, 'What do we do about this?' We said, 'How about we just consider it a non-problem until it becomes a problem? If anybody gets sick in space you can bring us home. Then we'll deal with it as a problem, but let's consider it a non-problem.'"

Curiously, according to Margaret Weitekamp, a space historian at the Smithsonian National Air and Space Museum, there are no known studies on menstruation in zero-gravity environments, meaning that for as much conversation as there was around it, no one tested whether or not it really was a problem. There were, however, a series of tests in the 1960s through the Lovelace Women in Space Program, which was designed to test if women were physically fit for space travel.

Nineteen women were selected for the Lovelace studies, which included a series of rigorous physical exams identical to ones that male astronaut candidates had undergone (plus a gynecological exam). The researchers speculated that women might actually fare better in space, since they are, on average, smaller than men. Indeed, the researchers noted that more women passed the exams with "no medical reservations" than men. But when it came to the gynecological exam, there was a problem: The menstrual cycle might alter a female astronaut's ability to do her job. As the researchers noted in their report, "the intricacies of matching a temperamental psychophysiologic human and the complicated machine are many and, obviously, both need to be ready at the same time." In other words, you can't have a hormonal woman running an aerospace operation. Because of this, the researchers concluded that "it seems doubtful that women will be in demand for space roles in the very near future."

Eventually, of course, NASA did decide to send women into space. They'd learned that women were anatomically well suited for space travel, plus they took up less space, ate less food, and consumed fewer resources. Regarding periods, medics decided to treat space menstruation like Earth menstruation and see what happened.

There was another question, though: How were they going to deal with all that extra blood? Space waste was a big enough problem in itself. NASA had already developed a special space toilet with a suction feature (cup-like shape for women, cone-like shape for men) to properly store waste and seat belts, so that astronauts didn't float away while doing their business. They had also created something called a Disposable Absorption Containment Trunk (DACT)—a cross between bike shorts and a super-absorbent adult diaper—which could be worn by both men and women during launches or spacewalks, to collect waste when space toilets weren't available. But if women were going to potentially bleed in space, how were they going to absorb that?

As it turns out, there were no specially designed space tampons—women astronauts could use the same supplies they used on Earth. The bigger question, it seems, was how many tampons a woman in space might need. There's a passage in Sally Ride's oral history where she describes preparing for her first flight as the first woman in space:

That conversation went like this:

"Is 100 the right number?"

"No. That would not be the right number."

In Sally Ride's biography, there's another great scene of her discovering the string of 100 or so tampons that had been tied together, like a strip of sausages, so that they wouldn't float away.

For more on Sally Ride, check out Motherboard's brief history of the first women in space.

It's not clear just how many women have bled in space, in part because many female astronauts choose to suppress their menstrual cycles with oral contraceptives. (No periods, no problems.) But that's a shame, according to William J. Rowe, a professor of medicine. In an article in the Journal of Men's Health and Gender, Rowe argues that menstruating women actually have an advantage in space, since menstruating causes women to lose iron. Astronauts in space often experience increased iron levels, which can be "extremely toxic because it is conducive to high oxidative stress."

Could period blood be a woman astronaut's secret superpower? It's possible. For now, though, we know that zero-gravity menstruation looks a lot like earthbound menstruation.

As Seddon recalled in her oral history, "I'm not totally sure who had the first period in space, but they came back and said, 'Period in space, just like period on the ground. Don't worry about it.'"

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