Some links:
Review: The best apps to keep track of 'Aunt Flo' inconspicuously ...
'Aunt Flo” and the Female Athlete (from BlogHer Sports) Is it bad if you play sports when you're on your period? What's better, a pad or a tampon?
Did you lose because you had your period?
Can you play rugby on your period .and how can u reduce the pain..please help.(female rugby player)?
Curse or myth - do periods affect performance?