But I do have to ask - what exactly would you be gaining by having your characters powers linked to a menstrual cycle as opposed to just a lunar cycle - or any other cycle for that matter, I'm really confused as to what experience your are trying to achieve. And how do you expect your DM to accommodate this aspect of your character - other than just noting the date and what bonuses/penalties you have - which could apply to any conditional power scheme.
A writer once told me it isn't the powers & virtues that most define interesting characters, its their flaws. Look at the original 7 members of Justice League of America: four of them were virtually gods! Superman without his weaknesses to kryptonite and magic, Wonder Woman without her weakness of being bound by a male (germane to this thread, as it happens), Green Lantern without his weakness to the color yellow and The Martian Manhunter without his weakness to fire would be virtually unstoppable. Their stories would be boring tales of how they found the evildoers in ones and in groups and, by themselves, inexorably usher in Utopia. The only ones who could challenge them would be those who were similarly gifted in power.
But their flaws give even Joe-Lex Luthor a chance to make something interesting happen.
So what I'm aiming for depends upon the exact mystic tradition I was modeling.
If I were modeling a PC's powers being linked to her cycle, I'd design her so that her powers waxed and waned accordingly- RPG system & campaign permitting, of course.* Sometimes she'd be extremely powerful, sometimes she would be virtually powerless. How she'd cope would make for interesting scenarios. Foes who know of this flux could plan accordingly and strike when she was at her weakest- a classic storyline.
For characters with the "all or nothing" version of this, a moment of weakness means utter destruction. Succumb to your baser instincts, the sway of alcohol, a love philtre, or an unspeakable crime and you're ejected from your chosen path forever. This can make for a very extreme personalities- a very guarded person, private to the point of seeming unhuman; perhaps one who tempts fate- but regardless, always aware that everything they value could be lost in minutes.
For a regular mage, incarceration may be a temporary inconvenience. For a mage like this, incarceration could lead to powerlessness...and death. Therin lies extreme motivation to avoid capture, almost to the point of desperation.
This was part of what shaped the psyches of characters like Lythande (Thieves' World), Gillian (Bell, Book and Candle), Kahlan (Legend of the Seeker) and many other female mystics in literature and pop culture. There is a dramatic tension inherent within the character itself.
* FWIW, there have been a rare few male characters with their powers fluctuating on the same lunar cycle- werewolves, Moon Knight and a few others- but they're the exception.