So what even is menstrual leave? Do women get extra paid time off days? Or is it just, they're allowed to use sick days for menstruation? Is there some different process for using "menstrual leave" vs sick leave?
Would have to be answered by someone knowledeable of the polish law. I assume at least we talk about their polish studio.
For me menstrual leave sounds just like plain BS.
Here any women (or men) can take sick days kinda almost unlimited. I think some weeks(!) have to be paid by your employer before the state will take over and pay for quite some time a more limited amount. Or something like that. I think only people that are really sick, figure out how good our system actually is.
Since I have no idea about how bad and long menstrual pain actually is, I assume females might feel one or two days a month sick enough to check out, as per what they tell here about use of this policy, so that is certainly covered without having to tell your employer that it is this. A monthly pattern though might especially in small companies be not that hard to be figured out.
Having a rather limited number of sick days seems entirely stupid imho. Sick means stay at home, especially if it is contagious or you being not entirely fit being dangerous by driving around operating machines or whatever.
But allocating it to specific illnesses appears even more stupid. My employer has no right at all to even know why I am sick. I don't have to tell them anything. All I have to bring is a note from any doctor that I am/was sick, were at the dentist, had a check up whatever. I guess if they are a bit nosey and not purposely ignorant they clearly can read who wrote it and that might tell what it might be, but if i have a heart problem, cancer, monthly bleedings, migraine, had a nose job or did hair implants, shot myself in the foot isn't something they need to know. Some expected return date or whatever is expected though. You don't have to be a dick about it of course, unless you are actually comatose just playing dead forever is not nice and not informing your boss and colleagues on how to proceed short or even long term.