Knowyourmeme tells about this prank and how some women started some protests for being able to free bleed* their periods. It shows some twitter tweets about defending this practice.
This other pages somehow show that, at least in theory, the campaign was continued to at least a seemingly acceptable degree:
This makes the fact that the campaign was serious, with lots of women participating in it, and not a continuation of the prank pretty possible, but on the other hand I find that asking for free bleeding a period is something let's say... unhygienic, dirty and smelly, so wanting to do it would be strange from my point of view.
Claim clarified due to request :
Was there a serious campaign in which at least thousands of women participated (what I consider a serious campaign) for their right to free bleed their period being the origin of the protest the prank done by 4chan which is indicated in the first linked article? I mean even if the campaign existed somehow before and wasn't a prank, it suddenly turned big from that event.
* The practice of abstaining from using feminine hygiene products during menstruation