Hi Queen D. Different people have quite different reactions to this. Some find it has no effect at all while others find it delays their cycles. If you are worried about it you might want to plan your Cleanse timing around it.
Not sure what you're scared of? Its definitely never a good thing to be 'eating like there's no tomorrow', and especially not before a Cleanse. The fact that you are NOT eating is what's going to allow your body time to begin to recover itself and allow it to address its backlog. Over 60% of your energy every day is spent digesting the food you are consuming.
Its high time you learn to trust your body, one of the most spectacularly evolved organisms on this planet and far far more capable than you are giving it credit for. Leave it alone (as you will during the Cleanse) and re-experience for yourself its amazing powers of healing and rejuvenation. When last did you ever have to worry about beating your heart, breathing, digesting food and making trillions of new cells every second...?
As for menstrual cycles Stanley Burroughs has this to say:
"Blend a part of the lemon skin and pulp with the lemonade in a blender for further cleansing and laxative effect. (Note: commercially produced lemons may have had their skins dyed with yellow coloring and may have been subjected to poisonous insect sprays -- be sure to peel off the outer skin if you cannot get uncolored, organically grown lemons.) The properties in the lemon skin also act as a hemostatic to prevent excess bleeding and to prevent clotting internally should there be any such prevailing condition. (Don't worry -- normal conditions will continue during the menstrual periods.)
"I am responsible - the creator of my own experience."