It’s been more than 50 years since the first woman was launched into space, but scientists are still studying the best way to manage astronauts’ menstrual cycles.
In a new paper, Varsha Jain from King’s College London and Virginia E. Wotring from Baylor College of Medicine discuss the logistical challenges female astronauts face while getting their periods in space.
For example, “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, thus idealizing the minimization of breakthrough bleeding during menstrual suppression,” the authors write.
The paper, published Thursday in Nature’s npj Microgravity, compares the efficacy of various contraceptives, both in space and during the selection and training processes, for astronauts who choose to induce amenorrhea, the medical term for suppressing menstruation.
The authors recommend giving female astronauts an “up-to-date, evidence-based, comprehensive education” in order to “empower them to make informed decisions regarding menstrual suppression while respecting their autonomy.”
Many women astronauts have used the birth control pill, the paper notes -- however this method becomes less efficient over extended periods of time.
A continuous regimen for a 3-year mission would require 1,100 pills, the authors estimate, which also come with excessive packaging.
Additionally, “Drug stability has not been tested for hormonal medications over such a long time in space or with the impact of deep-space radiation,” they write.
The ideal space contraceptive
From candidate selection to spaceflight mission, becoming an astronaut can take up to 11 uninterrupted years, the paper estimates.
“The ideal contraceptive method would therefore help ensure effective amenorrhea as well as higher adherence rates in order to reduce pregnancy risk,” the paper notes.
The study looks at several different contraceptive methods, including the combined oral contraceptive pill (the birth control pill), depot medroxyprogesterone acetate (Depo-Provera injections) and long-acting reversible contraceptives such as levonorgestrel intrauterine devices (LNG-IUDs) and birth control implants.
Ultimately, despite a history of astronauts using the birth control pill, the authors say longer-term methods should be considered.
Specifically, they recommend LNG-IUDs.
“With the LNG-IUD currently licensed for five years versus three years for the implant, our recommendations would lie with the LNG-IUD due to time scales over which astronauts may require medically induced amenorrhea,” the paper says.
The paper also says that “bleeding irregularities” in implant users has been successfully treated with concurrent birth control pill use. Though the combination has not been investigated, the authors suggest it could be a viable option for female astronauts.
Ultimately, the authors say more research into the subject is necessary, and that lessons could be learned from military personnel who undergo similar “austere” conditions to astronauts.
“The uniqueness of the spaceflight environment provides many challenges in conducting research,” the study notes. “The number of subjects required by clinical studies cannot be matched by the number of current active female astronauts.”
