Nota bene. When doing a Google search of the FAQ, be sure to double-quote 'menstruation', as in

"menstruation" inurl:reddit.com/r/AskHistorians/wiki

That makes it look for the literal term. Without the double quotes, it includes synonyms, one of which is 'period', which has a lot of false hits in a historial subreddit.

Nota bene. When you see the hits, though, they look like

https://www.reddit.com/r/AskHistorians/wiki/health?v=d79adc9c-bc95-11e3-9996...

The trailing "?v=..." is an indication that it's a previous version of the FAQ. I can't find anything in the current FAQ.

Anyway. Mentioning previous answers is not intended to discourage follow-on questions, information, or debate.

There's "The AskHistorians Podcast Episode 32 Discussion Post - Early Modern Medicine & Women's Health" via https://www.reddit.com/r/AskHistorians/comments/2ywtdj/the_askhistorians_podcast_episode_32_discussion/ .

"Did women wear menstrual belts without underwear?" at https://www.reddit.com/r/AskHistorians/comments/7665s2/did_women_wear_menstrual_belts_without_underwear/ got one answer, from /u/chocolatepot .

"Have bathrooms always be segregated by gender? If not, when did this practice begin?" had a side discussion under https://www.reddit.com/r/AskHistorians/comments/6xb6qn/have_bathrooms_always_be_segregated_by_gender_if/dmg02qn/ . chocolatepot again. And elcarath provided some links:

"How did women deal with periods before tampons/pads were invented?" at https://www.reddit.com/r/AskHistorians/comments/6nysk3/how_did_women_deal_with_periods_before/ . chocolatepot again, and /u/Gorrest-Fump, though the latter answer mentions only later periods (sorry).

In there is also the link to /u/sunagainstgold 's answer that chocolatepot couldn't find a month later: "How did women deal with periods in medieval times?" at https://www.reddit.com/r/AskHistorians/comments/55yvw7/how_did_women_deal_with_periods_in_medieval_times/ . In there, isabelladangelo notes "There have been finds of closed crotch underwear both in the castle digs, the Italian case you mention, and in woodcuts of the period.", pointing to https://www.historyextra.com/period/medieval/medieval-underwear-bras-pants-and-lingerie-in-the-middle-ages/ . There's also a note from Aelintari : Protestant polemic as a source of info!

"How did women cope with personal hygiene particularly menstruation in a Poor/Workhouse?" at https://www.reddit.com/r/AskHistorians/comments/3obl8p/how_did_women_cope_with_personal_hygiene/ , with info from colevintage.