the big connection that i used to see when i had periods was that if my SI was going to be loose, misaligned, and inflamed, then it would happen about a day or two into my period, so i'd have to be really careful around that time, constantly adjust myself with a few isometric tricks my PT and physiatrist taught me, and even stay in bed with ice packs and wait it out and minimize the "damage" (inflammation, weakened muscles from spasming, etc) for a few days.
sue