What Happens When You Get Your Period in Space?

For female astronauts living on the International Space Station, dealing with menstruation can be a huge challenge. "The Space Station is essentially a giant tin can. Hygiene is not fantastic up there," and there's limited water for washing up, said "space gynecologist" Dr. Varsha Jain, visiting researcher at the Centre of Human and Aerospace Physiological Sciences at King's College London.

Beyond that, only one of two Space Station toilets can accept blood, which is treated as a contaminant, she said. (The other one recycles urine into drinking water.) "The practicalities of changing a tampon or pad when everything is floating around [in zero gravity] is not actually easy," continued Jain, who spends part of the year in Houston, where the astronaut corps is based, at the NASA Johnson Space Center.

In a new study, published in the journal npj Microgravity, Jain looks at how female astronauts can safely skip their periods, if they so decide.

"It's really important to note this is a completely personal choice," she told Motherboard. "There are no regulations from NASA or the European Space Agency." That said, even before the mission, these women are undergoing rigorous training and keep "crazy" schedules, she said—doing "deep-sea diving, survival training," and other activities that might make dealing with their periods not really ideal.

Studies in the military have shown that women typically want to suppress their periods when they're deployed, according to her new paper. It makes sense to think that the same is true of female astronauts, a group that's still severely understudied.

As of now, female astronauts' preferred way to skip their periods in space is to take birth control pills for long, continuous stretches, according to Jain. "Thoughts on whether women need to menstruate every month vary widely and have cultural determinants," the study says, "but menstrual suppression is gaining favor and becoming more common." Instead of taking three weeks' worth of pills, and then a week of placebos, which allows for a "withdrawal bleed" (essentially a fake period), women who choose to suppress it altogether just keep taking the hormone pills straight through their cycle.

But taking a giant pack of birth control pills up into space isn't the best option. For a three-year mission to Mars, a female astronaut would need to carry about 1,100 pills with her, adding mass and bulky garbage to carry, Jain's study notes.

Contraceptive pills also create risk for developing "clots in legs or lungs," but no female astronaut has suffered from something like that, she said. Astronauts are as fit as they possibly can be, and "in such a healthy population, complications like that don't tend to occur."

Even so, we haven't flown that many women, Jain acknowledged—of the 543 astronauts who've been to space since 1961, when manned spaceflight began, just 11 percent are female—so we don't really know if these problems would start to show up in bigger groups.

"It's a really small number we've got in space," she said. "When commercial spaceflight starts taking off," it might turn into a problem, she continued, especially in female spacefarers who aren't as healthy as the superelite astronaut corps.

Longer-acting reversible contraceptives, like IUDs or implants, haven't been studied yet in astronauts. They could be a good option, Jain said, but scientists don't really know if the high Gs during launch or landing would damage an implant or IUD, or cause it to move around.

Jain thinks we need to do a better job of educating female astronauts about their options around birth control and menstrual suppression before they head into space, so they don't find themselves dealing with an unwanted period when they're up on the Station, or worse, stuck on Mars without any pads or tampons—or birth control pills.