A real helpful hint for riding during menstruation is to cut the string of the tampon, that way you eliminate the chafing effect of the string, especially on long rides. Where was that link to that kooky device? Some sort of menstrating cup or something? Anyway, a tampon with the string cut short works fine for me. Now, as to the problem of swellling ankles, those are the days that I will choose to wear low cut socks. That pesky water weight gain can lead to unsighly cankle overlap on socks that go higher up the ankle. I find that I am most "off balance" a few days before and the first few days into my period. Not quite sure why that is as I don't really suffer from any other noticeable premenstrual symptoms. Of course, there are some in my life who might argue with me on that one. All of these inconviences are minor and I find that I am able to ride during my period without problems, although I am a bit more sluggish and don't tend to do as well in races.
Sabine