I found this posted in another discussion through a Google search:
"While in Brazil I asked the Shaman I worked with what his opinion was about women drinking on their moon. He told me that traditionally women did not do so because the extra power that they hold during their cycle could create extremely intense journeys. We are very open during our moon and I suppose that it was believed women could attract spirits into them like a magnet. (Where's the credit for being able to control such instances?)
Since I was to begin my cycle during my two weeks of drinking I contemplated drinking or not. His response was that I could drink, but to be aware that aya would increase my blood flow.
The day I started my cycle I drank, grateful that my flow was at its lightest. I kept checking for an increase in blood, but I was fine. My journey was deep and intense, but no more than before. Although I was "super" attuned with my fellow voyagers.
Two days later I bled like never before. Soaking through super-duper plus absorbancy tampons and pads. One night I woke up every two hours covered in blood. The bed was a mess, I had to shower; finally I "slept" on top of many towels. It definitely affected my integration process. I'm not sure if I would drink again while on my moon."