Okay - seriously - I haven't seen much on this topic but it needs to be mentioned - menstruation. I was about to cancel after training so hard and perfect weather forecast but it's an individual decision.
One - how one feels normally during day one, two, etc.
Two - how to maintain personal hygiene.
Three - ligament, tendons changes with your cycle and its potential effects.
Four - bears, critters, etc. are they a factor?
My experience -
1. I was more tired and less stamina I think but could have been just the less sleep and altitude.
2. I took a chance and luckily found, bought and used the Divacup at Whole Foods Market with a trial run the day before we left. It takes a little getting the hang of to use, so also wore a pad for leakage. Took unscented baby wipes, and fresh water to clean. Collected all and disposed of the blood in the WAG bag. (Only problems was leg cramps from squatting for so long after hiking- okay stop laughing!!!)
3. My knees in particular are much looser, so I must be very careful to use my butt, leg and core muscles even more so.
4. No - all the research, and people in the know I've talked to say so.