This post was born as a response to a question sent in by Carla regarding how female astronauts deal with their menstrual cycle during long duration mission in space. There are no rules that require or, on the contrary, prohibit to suppress the menstrual cycle during a space mission. To tell you the truth not even mere recommendations exist: every astronaut decides freely according to their preference. It is of course a good idea to inform the flight surgeon about the decision; the latter must be familiar with all aspects of the astronaut’s health. Apart from this, it is a completely a personal choice. From what I have heard from my colleagues, I believe that often considerations of practicality make it preferable to choose for pharmacological suppression. It is not, however, any different from what is commonly practiced by many women: those who typically use the “classic” contraceptive pill is in fact already suppressing the menstrual cycle. The bleeding during the week of interruption (or placebo), are not a real period, but a so-called withdrawal bleeding. If you decide instead of having a regular menstrual cycle on board, it’s not a problem. There are stocks of sanitary products onboard and the “bother” is really a minor one: I would not want to change, for example, having to need to shave my face (and maybe even the head) each morning in weightlessness!