Menstruation and alcohol absorption

Today, an epiphany.

From Flow:

"Alcohol tolerance also varies depending on where on is in one's cycle. Unlike men, who seem capable of absorbing the same amount of beer no matter what time of the month it is, women clearly fluctuate: they seem to hold their liquor the best during their flow, their worse in the week before."

This explains so much. Perhaps personal investigatory studies are in order...