It wouldn't surprise me in the least. It seems to me that as far as womanhood goes, it's either bad and vile or powerful. Some cultures find the menstrual period to be unclean. Other cultures, including the Navajo, find this period of time and the blood from it to be sacred. To those, it's a celebration of womanhood.

I also wouldn't be surprised if some cultures drank it as a way to receive power. I know that the Navajo women are very careful about disposing of their menstrual fluids because they are heavily sought after by wicked medicine men. This rationale of equating power to menstrual fluid may not be rubbish at all. We're talking about hormone laden blood, cells, ovum. It's not just simple blood.

If this was done, I must say that they really had to have a deeply ingrained different opinion of menstruation. The idea of drinking it to most of us is probably nauseating and I suspect that this would be the consensus of people even a thousand years ago. Did the Templars drink it? Who knows but it would explain a bit of why they were treated so brutally at the end. Christianity, in general, is not very female friendly. It would certainly create a very bad scenario for the Templars if they were found out.