American Astronaut Margaret Rhea Seddon logged three separate space flights between 1985 and 1993 for stretches of 7 days, 9 days, and 14 days. In an oral history, Seddon reveals that a lot of NASA scientists expressed concerns before her trips about menstruation. It was, she says, one of the unknowns of space.

“A lot of people predicted retrograde flow of menstrual blood, and it would get out in your abdomen, get peritonitis, and horrible things would happen,” Seddon said. “All the women were going, “I don’t think so.” But you couldn’t prove it or disprove it.”

After convincing the scientists to “consider it a non-problem,” the first female astronaut who had her period in space soon discovered it to be just like having your period on earth, Seddon says, adding that a second debate arose: How many feminine hygiene products get stored onboard the spacecraft?

Today, a likely answer is “none,” according to researchers at King's College London and Baylor College of Medicine. Having explored the issue, they suggest menstrual suppression may be preferred by female astronauts on longer hauls or for extended visits to the International Space Station (ISS).

Orbital Concerns

In the novel Minus Time, Barbara Urie, a mother and astronaut, attempts to set a record for human space habitation. “I imagine that my astronaut Barbara, who was very set on being part of a long-term mission, would have chosen to use some kind of menstruation suppression,” author Catherine Bush, tells Medical Daily. “She would likely have chosen something subdermal.”

Since November 2000, the ISS microgravity laboratory has been continuously occupied, hosting an international crew of six people. As they live and work, the crew orbits the Earth every 90 minutes, traveling at a speed of five miles per second. A total of 222 people from 18 countries have visited since 2000, and of those total visitors, 58 were women: 49 Americans (who ranged in age from 26 to 47), eight Soviets, and two Chinese, a NASA spokesperson reports.

“For the most recently chosen class of new astronaut candidates, 4 of the 8 are women,” Dr. Virginia Wotring, senior author and assistant professor at Baylor’s Center for Space Medicine, tells Medical Daily. She explains her menstruation in space study began when Dr. Polk, head of Space Medicine at Johnson Space Center, asked if certain oral contraceptives had a lower risk of blood clots than others. (Using oral contraceptives is linked to doubling the risk of clots.)

“We have now expanded on that question to evaluate the blood clot risk of other contraceptive and/or menses suppression therapies as well,” she says. Wotring and her co-author Dr. Varsha Jain note the practicalities of menstruating during pre-flight training or spaceflight can be challenging. For short duration missions, menstrual cycles can to be timed according to mission dates. Menstrual suppression may be preferable, though full amenities exist for astronauts choosing to menstruate in space.

Seddon recalls doing a “worst case” scenario evaluation, where she attempted to calculate the maximum number of tampons or pads necessary. “Because we didn’t know how it would be different up there…Most of the women said, ‘I would never, ever use that many.’” According to Seddon, having to pack such an excessive number of feminine hygiene products meant less room to pack other items, including clothes.

Menstrual suppression, then, offers a packing advantage along with other benefits.

Feminine Endurance

“The waste disposal systems onboard the U.S. side of the International Space Station that reclaim water from urine were not designed to handle menstrual blood,” wrote Wotring and Jain. Plus, packaging of feminine hygiene products contributes to “upmass” (total payload carried into space), while also causing additional trash. With limited wash water and potential difficulties with changing a tampon in microgravity, the practicalities of menstrual hygiene during spaceflight might also be challenging.

During long-duration missions, then, some astronauts have taken the combined oral contraceptive (COC) pill to prevent menstrual flow. Yet, the authors predict a three-year exploration class mission would require approximately 1,100 pills, which would add considerable mass and disposal requirements for the flight.

Long-acting reversible contraceptives (LARCs), such as beneath-the-skin implants and IUDs, appear to be safe and reliable methods of suppression while also possessing a number of advantages for spaceflight, say Wotring and Jain.

A LARC would remove upmass, packaging, and waste issues. The device could be inserted prior to a mission with no replacement necessary during flight. In all likelihood, an astronaut using a LARC would be able to perform her tasks unhindered, though preflight testing might be necessary to see whether the implant might rub or catch on an extra-vehicular activity suit or specialist equipment. And, no reports suggest the high gravitational force loads which accompany launch and landing would damage a subdermal implant or shift the position of an IUD.

One issue requiring further study is the effect of hormone treatments on bone mineral density. Both men and women astronauts are known to lose bone at higher rates than on Earth. Previous studies indicate a temporary, higher than usual loss of bone mass density occurs with some contraception options, so further research is needed.

“If we want space missions to be fully human, and bring all of our best attributes as a species to the challenges of being in space, we need both men and women to ‘(hu)man’ these missions,” says Bush.

Until the number of active female astronauts meets the number of participants required for a clinical study, the authors suggest using pharmacological data from spaceflights combined with ground-based studies to investigate potential effects of LARCs during spaceflight.

“LARCs might be appropriate for many women — on Earth and in austere environments like a military deployment,” says Wotring. “Since LARCs may be effective for long periods of time (3 years), they may be especially useful for women who find it difficult to access a clinic or pharmacy on a regular basis.” She adds LARCs are in common use in Europe and the United Kingdom, and women who are considering this option might discuss it with their doctors.

“We’re really hoping to call a little more attention to the wide spectrum contraceptive choices available to all women, as well as to the notion of menses suppression as a potentially desirable side-effect,” Wotring says. Ultimately, she believes it's a woman’s choice to suppress or not, no matter whether her explorations remain terrestrial or in wondrous space.

Source: Jain V, Wotring VE. Medically Induced Amenorrhea in Female Astronauts. Microgravity. 2016.